Bad plugs, bad gas, or clogged cats?

[4eyedconekiller]

Hey folks!

New SHO owner here. Bought the car, and have been traveling for work, so I haven’t had an opportunity to get any work done on the car.

Car is mildly modded - Catted SW downpipes, SW catback, 3 bar MAP, Airaid CAI, and Performance tune from Unleashed. Also has NGK LTR7IX-11 plugs (one step colder iridium). All mods done in last 40k.

Guy hadn’t driven it or started it in two months prior to me buying it.
At 30-40% throttle around 3k RPM, I get a pretty solid stumble/stutter. I also had a hard hesitation at WOT during a pass, with the DTC flashing. I wasn’t able to check codes at that moment, but my plan is to do exactly that when I get back to Mississippi next week.

Actions taken:
- So, I’ve run one tank of gas almost dry, and refilled.
- Talked to unleashed. They recommended a new tune and fresh plugs.

Plans:
- Clean air filter
- Finish off second tank of gas
- Check DTC’s
- Pull and inspect plugs
- Oil Change (past due)

I’ve heard good things about unleashed, but before I start throwing money at it I want to make sure its not a hard part. My biggest culprits at this point are Trashy gas, stopped up fuel filter, bad plugs, or plugged cats.

Anything else you guys would recommend???

 

[bamsho]

Change plugs.  Most of owners are running these plugs from Ford Performance.  They are M-12405-35T.  You can get them from Summit, or the tuners. 


I had trouble with NGKs, but also could be getting blow out cause the gap is too big.  Gap should be a max of .030 for tuned cars.


Hope this helps.

 

[Admin]

Hard stumble with flashing cel is almost always a misfire.

I pull the DTC as it will tell you which cylinder is getting the misfire.

Check plugs and coils. Move the coil to a different cylinder to see if the issue follows.

People have had issues with the NGK plugs FWIW.

Good luck!

 

[4eyedconekiller]

I had issues with that thought too. I don’t like the iridium stuff, but I’m open. NGK’s are what Unleashed recommended. I prefer a copper plug for FI cars, but I’ve not had a boosted gasoline powered vehicle in quite a while. I’ll search for em, unless you know of the ideal solution.

 

[TopherSho]

Clear the DTC/CEL then reproduce and pull the CEL .. it takes a very serious chain of misfires to trigger the code so i have some concerns.

Plugs swap for sure,  swap coils after seeing what cylinder is/if misfiring. 


Pull a BACKUP your current tune and send it to Torrie.. See if he 'recognizes' the car *and* also see if there is a E tune on it by some strange chance.  Maybe get some history. 

but .. As soon as you said the previous driver had not drove it in months I puckered up quite a bit,  it kinda sounds like a abandoned project ... and makes me concerned there might be a chance they could not figure out the tune issue.


Last .. go get some c20 and or 97 ethanol free gas .. put in 4 gallons to a empty tank and retest ..

good luck post back ..

 

[4eyedconekiller]

Clear the DTC/CEL then reproduce and pull the CEL .. it takes a very serious chain of misfires to trigger the code so i have some concerns.

Plugs swap for sure,  swap coils after seeing what cylinder is/if misfiring. 


Pull a BACKUP your current tune and send it to Torrie.. See if he 'recognizes' the car *and* also see if there is a E tune on it by some strange chance.  Maybe get some history. 

but .. As soon as you said the previous driver had not drove it in months I puckered up quite a bit,  it kinda sounds like a abandoned project ... and makes me concerned there might be a chance they could not figure out the tune issue.


Last .. go get some c20 and or 97 ethanol free gas .. put in 4 gallons to a empty tank and retest ..

good luck post back ..

Bought a set of SP542's yesterday. Cleared the codes, and had it act up in a BAD way last night. Made another pass, started to stumble, and BAM! It fell on it's face, and started to miss horribly. CEL flashing slowly for roughly a minute or so. Could smell hot converter(s). Once the CEL stopped flashing, the missing stopped. I ws 10-ish minutes from home. Finally got to a stopping point, and checked codes. Only codes I've gotten are a P0420 and P0430. Nothing else. Prior owner says that codes have been present since downpipe swap, and he and Unleashed were unable to resolve it with the tune.

I'm going to pull a couple plugs and see what they look like tomorrow, but today I’ll kick on the  SCT x4, and make a  pull. I’ll turn AFR gauges on, but not sure what else.

Keep you folks posted.

 

[Admin]

Does the oil smell like gas?! I would check ASAP... this almost sounds like a stuck injector..

Usually you get other codes too but ya never know.

 

[GotGrip?]

So I had something very similar to this that was plaguing me for the last few weeks, I got dual cat code, then o2 sensor codes. After the o2 sensors were swapped out, I got a p219a. After screwing around for 2 weeks checking all the things the p219a covers it ended up being bank 1 injectors. Got a set of 6 for around $240 off rock auto, swapped them out and runs smooth now, no codes.


I would also check coils if its not a fuel issue but actually firing, I had an issue with my MSD coils that were misfiring but didn't throw a code for a couple days of driving. Might be worth looking in to.

 

[TopherSho]

Clear the DTC/CEL then reproduce and pull the CEL .. it takes a very serious chain of misfires to trigger the code so i have some concerns.

Plugs swap for sure,  swap coils after seeing what cylinder is/if misfiring. 


Pull a BACKUP your current tune and send it to Torrie.. See if he 'recognizes' the car *and* also see if there is a E tune on it by some strange chance.  Maybe get some history. 

but .. As soon as you said the previous driver had not drove it in months I puckered up quite a bit,  it kinda sounds like a abandoned project ... and makes me concerned there might be a chance they could not figure out the tune issue.


Last .. go get some c20 and or 97 ethanol free gas .. put in 4 gallons to a empty tank and retest ..

good luck post back ..

Bought a set of SP542's yesterday. Cleared the codes, and had it act up in a BAD way last night. Made another pass, started to stumble, and BAM! It fell on it's face, and started to miss horribly. CEL flashing slowly for roughly a minute or so. Could smell hot converter(s). Once the CEL stopped flashing, the missing stopped. I ws 10-ish minutes from home. Finally got to a stopping point, and checked codes. Only codes I've gotten are a P0420 and P0430. Nothing else. Prior owner says that codes have been present since downpipe swap, and he and Unleashed were unable to resolve it with the tune.

I'm going to pull a couple plugs and see what they look like tomorrow, but today I’ll kick on the  SCT x4, and make a  pull. I’ll turn AFR gauges on, but not sure what else.

Keep you folks posted.

The ''flashing cel'' that goes away is a plug that is wet or from a hot spot from an ENORMOUS amount of carbon build up. 


Two questions:
did you keep the old plugs and did you number them?  (post pics)
has the car been running octane boosters... in the TRUCKS the 3.5 eats boosters without issue.. for the SHO\MKS the boosters gunk things up VERY badly, ruins o2 sensors, plugs and cats

if the plugs ''look ok'' and you or the previous owner was not running boosters this is very likely a bad injector(s) and you should stop driving immediately ..

 

[TopherSho]

Clear the DTC/CEL then reproduce and pull the CEL .. it takes a very serious chain of misfires to trigger the code so i have some concerns.

Plugs swap for sure,  swap coils after seeing what cylinder is/if misfiring. 


Pull a BACKUP your current tune and send it to Torrie.. See if he 'recognizes' the car *and* also see if there is a E tune on it by some strange chance.  Maybe get some history. 

but .. As soon as you said the previous driver had not drove it in months I puckered up quite a bit,  it kinda sounds like a abandoned project ... and makes me concerned there might be a chance they could not figure out the tune issue.


Last .. go get some c20 and or 97 ethanol free gas .. put in 4 gallons to a empty tank and retest ..

good luck post back ..

Bought a set of SP542's yesterday. Cleared the codes, and had it act up in a BAD way last night. Made another pass, started to stumble, and BAM! It fell on it's face, and started to miss horribly. CEL flashing slowly for roughly a minute or so. Could smell hot converter(s). Once the CEL stopped flashing, the missing stopped. I ws 10-ish minutes from home. Finally got to a stopping point, and checked codes. Only codes I've gotten are a P0420 and P0430. Nothing else. Prior owner says that codes have been present since downpipe swap, and he and Unleashed were unable to resolve it with the tune.

I'm going to pull a couple plugs and see what they look like tomorrow, but today I’ll kick on the  SCT x4, and make a  pull. I’ll turn AFR gauges on, but not sure what else.

Keep you folks posted.

The ''flashing cel'' that goes away is a plug that is wet or from a hot spot from an ENORMOUS amount of carbon build up. 


Two questions:
did you keep the old plugs and did you number them?  (post pics)
has the car been running octane boosters... in the TRUCKS the 3.5 eats boosters without issue.. for the SHO\MKS the boosters gunk things up VERY badly, ruins o2 sensors, plugs and cats

if the plugs ''look ok'' and you or the previous owner was not running boosters this is very likely a bad injector(s) and you should stop driving immediately ..

Adding one additional but less likely possibility .. it is possible and has been seen that gunked up primary O2's can cause massive over fueling leading to burning in the cats ...

 

[4eyedconekiller]

Man, thanks so much for all the replies!!! Stuck injector or gummed 02's make complete sense.

I wound up parking the car, and picking up my ram from the dealer. In the process, I ran out of time before I had to fly back out for work. I"m running on in-flight WIFI as I type.

I'll dig into it shortly after I get back home after the first of the year. Can anyone give me a plug numbering diagram or anything???

Plans are to pull (and replace) plugs, pull upstream 02's, and see what things look like. I'm puzzled that it's showing issues on both banks. I can't wait to resolve this so I can fully enjoy the car - then it's on to more fun stuff, like a chrome delete, deciding on gauges vs monitors, getting rid of the TERRIBLE exhaust drone, and the rough ride. My RAM 1500 is like a Cadillac in comparison, lol.

MERRY CHRISTMAS YOU ALL!!!

 

[4eyedconekiller]

Finally got around to changing the plugs... SP542’s at .028.

Plugs look well worn, but I’d like you guys thoughts. I don’t see any crazy discoloration or missing pieces...

 

[TopherSho]

Plug COLOR is great.  Not rich Not orange or yellow.  So no issues with fueling (that is visible anyways) and no weird colors so not a upstream issue.

New plugs in ?  How is the behavior there ?

 

[SHOdded]

If you have cat codes, you likely have stuck injectors.  On naturally aspirated vehicles, you can run bg 44k or similar pro cleaner thru the system to get them unstuck.  Due to the pressures involved, you will want to try a GDI specific product, preferably at a shop, if you want to give it a go. They will have the induction cleaning systems to do it right.  Valvoline service centers for example.

If you change 1, change them all.

Misfires can also be caused by a) carbon buildup on the backs of the intake valves, b) crud from intercooler buildup being pulled into the intake, and c) tho rare on gen v, chafing knock sensor wires.

get ALL the fluids up to date:  coolant, trans, ptu, rdu, and brake.  Check for pooling oil in the turbo piping.  Check and clean out the intercooler.  Make sure all recalls - such as fuel pump delivery/control modules - are done.

Use SN+ (or later) oils only.  If you are in a hot climate, 10w30 may work better for you than 5w30.  Redline LWSP for ptu/rdu fluids recommended, or Amsoil Severe Gear of appropriate viscosity.  Motorcraft MERCON LV is fine for the trans, though i like Valvoline MAXLIFE MV better.  Coolant can be flushed for YELLOW, or go to a universal like Peak 10x / prestone 300k. If your SHO is speced for LV brake fluid, OEM is fine.

The first major mod you make should always be to establish a strong foundation.

 

[4eyedconekiller]

If you have cat codes, you likely have stuck injectors.  On naturally aspirated vehicles, you can run bg 44k or similar pro cleaner thru the system to get them unstuck.  Due to the pressures involved, you will want to try a GDI specific product, preferably at a shop, if you want to give it a go. They will have the induction cleaning systems to do it right.  Valvoline service centers for example.

If you change 1, change them all.

Misfires can also be caused by a) carbon buildup on the backs of the intake valves, b) crud from intercooler buildup being pulled into the intake, and c) tho rare on gen v, chafing knock sensor wires.

get ALL the fluids up to date:  coolant, trans, ptu, rdu, and brake.  Check for pooling oil in the turbo piping.  Check and clean out the intercooler.  Make sure all recalls - such as fuel pump delivery/control modules - are done.

Use SN+ (or later) oils only.  If you are in a hot climate, 10w30 may work better for you than 5w30.  Redline LWSP for ptu/rdu fluids recommended, or Amsoil Severe Gear of appropriate viscosity.  Motorcraft MERCON LV is fine for the trans, though i like Valvoline MAXLIFE MV better.  Coolant can be flushed for YELLOW, or go to a universal like Peak 10x / prestone 300k. If your SHO is speced for LV brake fluid, OEM is fine.

The first major mod you make should always be to establish a strong foundation.

Thanks! I work out of town, so I’ve had limited time. Will be changing the engine oil tomorrow. Currently quarantining till Monday, so clearing up as many of the out lying projects as I can. I’ll def check for the other things you suggested and check around for a fuel system cleaner like you suggested.

This ain’t my first rodeo, so Im Plugging away at the issues as I get my bases covered. I’m 100% sure that PTU oil or coolant wouldn’t be causing my issues, but they are on the list of TTD.

Plug COLOR is great.  Not rich Not orange or yellow.  So no issues with fueling (that is visible anyways) and no weird colors so not a upstream issue.

New plugs in ?  How is the behavior there ?

Ran like a CHAMP until the code came back up. Only acts up occasionally at WOT. Big puff of something out the tails if I go WOT after cruising a while. Mid throttle response is MUCH Improved.

Will post a video shortly of a pull.

 

[4eyedconekiller]

Try this and see if it works...

https://youtu.be/uwzwQ-twBn0

 

[TopherSho]

hmmm the fuel rail dropped into the 1100s,  anyone else non-meth have any input on their fuel rail pressure?  But afr was good.

AFR looks ok on the main display,  but i'd grab a data log of a run from 2nd to 3rd into 4th... need to look at the STFT and and the LTFT and OAR values to limit the chances of a Injector.. it will also show blips if it is sucking in gunk from the IC.

Go from there along with the full fluid run from SHOdded.. I'd also consider checking the PCV to ensure its not full of oil in addition to popping the hoses off the turbos to see if the tubes leak a fair amount of oil... hmm

 

[4eyedconekiller]

hmmm the fuel rail dropped into the 1100s,  anyone else non-meth have any input on their fuel rail pressure?  But afr was good.

AFR looks ok on the main display,  but i'd grab a data log of a run from 2nd to 3rd into 4th... need to look at the STFT and and the LTFT and OAR values to limit the chances of a Injector.. it will also show blips if it is sucking in gunk from the IC.

Go from there along with the full fluid run from SHOdded.. I'd also consider checking the PCV to ensure its not full of oil in addition to popping the hoses off the turbos to see if the tubes leak a fair amount of oil... hmm

I would’ve thought running an AFR of 10.x seemed a bit fat...

I’ve never done a data log. Will do some research on best way. Thanks for showing me the values to be mindful of.

Oil change will happen today, so while I’m draining the oil, I’ll try and check on everything else I can.

 

[TopherSho]

See if you can get the livelink gen ii software up and running on a windows box,  https://derivesystems.helpjuice.com/136470-info/346005-downloads

Then we will see if you have a config file on the tuner..  if you do we can easily go from there.

My last non-meth data log shows LAMDA from .82 down to .74.  So seeing it dip into the 10's on the guage is not great not but bad either depending on the signal quality from the O2 sensors.

If we can get the livelink running on a windows box we can easily datalog it and take a look.

Disclaimer : I have no opinion on Bamaperformance,  they had a easy to find datalog instructional without a laptop so i linked it


https://support.bamaperformance.com/hc/en-us/articles/202545589-How-to-Datalog-with-the-Bama-SCT-X4-SF4

go to this section (below) ::  see what config files exist on the device currently.

----
Recording the Datalog
For us to properly datalog your vehicle it is important that we get an idle, step and WOT datalog test. It is advised to save these as their own files to reduce file sizes.  Please click here for instructions How to Datalog Your Vehicle - SUPERCHARGED OWNERS PLEASE DO NOT GO WOT UNLESS INSTRUCTED
----

 

[ridered74]

hmmm the fuel rail dropped into the 1100s,  anyone else non-meth have any input on their fuel rail pressure?  But afr was good.

Scary as f. 1100 on WOT is no bueno.