Misfire under load detected today.

[Emilgevor]

00 S4 GIAC 93 TIP

While doing some friendly pulls with my buddies B7 A4 and some random S4 that spotted us today on the highway my cars CEL started blinking and i noticed that car started bogging between shifts. I pulled over and restarted the car. CEL stopped blinking and we went driving.
No issues between 5-13psi but as soon as car does 13-20psi thats when it starts misfiring and hesitating. If felt like as if car was choking.
I have new plugs with .28 gap and im pretty sure i have no boost leak since my gauge reads full 20psi. Could it be that my DVs need a stronger spring? I will put red one in tomorrow and see if that changes anything. Also afteri scanning for coded i got knock sensor code and P0303 <**** IIRC (misfires in bank 3). Will swap coils tomorrow as well and see if problem follows.
Other then what I listed what else can cause this issue?
Clogged cat?
MAF?
O2?

Any help would be appreciated.
Thanks

[00SantorinS4]

IIRC Blinking CEL = bad coil(s)

At least in my 02 1.8t that's what it meant.
Haven't had any issue's in my S with my coils.. knock on wood.

[SEXICÄN]

I almost bought a stage 3 car that had a similar issue of getting into boost it would bogg and cel would flash. Let of the gas and drive normal and cel would go away.

Sorry my post is no help, the guy I was gunna buy it from wouldn't let my shop find out the issue...

[Emilgevor]

Yeah these issues can be as simple as coils and as PITA as injectors and valve cover seals from what i heard. I have a $100 gift card from advanced auto so hoping its coil lol

[S4 00 2.7]

I agree with your guesses.

[RedB5S4]

My bet would be plugs or coils. What kind of plugs are you running and how 'new' are they? Ideally, they should be replaced every 10-15k miles on tuned cars. Your gap sounds fine, although you could probably go down to even .025 if you wanted to. Report back once you've swapped coils because then it should be pretty obvious where your problem is.

[Hyphy]

swap icm to see if it follows the other bank, besides that replace coils.

[Emilgevor]

Both ICM were replaced less then 20k ago.
Plugs are ACDelco Copper or Irridium I cant remember now. I wanted Bosch sidefire ones but they didnt have them. So i went with pregapped ones.
Im about to go out and replace SAP so while at it i will swap coil and take out plug to see what it looks like



These are the ones i took out to swap few months back and i know i didnt gap them but they looked like they are touching. Can plugs to that ? 0_o

[csosnowski]

that does NOT look good. I can tell from your pic that those are not gapped right. even at .028 there is a discernable gap.

those look distorted and crushed, the ground strap should not be squished like that. looks like those had way too wide of a gap to begin with and they got smashed.

re-gap your plugs using feeler gauges or a wire gap gauge.

and those plugs look to be in good shape, other than being mangled. you changed them?

what did you gap your new plugs to?

[Capt. Obvious]

My wife complains about misfire under load from me as well.

[Emilgevor]

New plugs came gapped at .28 i checked with a tool to make sure.
My question tho if i didnt gap previous plugs why are they so crushed?

[csosnowski]

no clue how those denso plugs got smashed. those were pk20tt's correct? they would have came pre-gapped at .032 i think, the car ran with those in it?

the delcos come pre-gapped at .028 which is nice for chipped cars.

[Vinchenzo51]

My wife complains about misfire under load from me as well.

LOL!

[Emilgevor]

Little update... I replaced both ICMs and reset the CEL. Drove a little until engine warmed up and then pressed on the pedal. After 10psi my whole car shakes still and will not accelerate. Car idles good no issues with it. I unplugged MAF to see if car dies or not. Car hesitated for a second and then stabilized. I drove with unplugged MAF and same thing would happen. CEL came one with P0102 since MAF was unplugged. As I mentioned before plugs were replaced about 1k ago and coils were functioning 100%. I have not gotten blinking CEL yet and no misfire codes yet. Not really sure what to look for anymore. Will scan it with VAG on tuesday but meanwhile want to see what you all think. Bad EGT? MAF?

[CELison]

This may sound odd but check your map. They rarely go out, but my rs4 map shit the bed a month ago. Would hesitate under load bad.

[Emilgevor]

How do you check if MAP good or bad?

[CELison]

you can log to see what pressure its reading, or swap it out with someone else's. If you just unplug it you will most likely go into limp mode and your car will run extremely choppy

[Emilgevor]

When my car kicks into limp mode and stays only at 5psi everything is good. Car accelerates well and no bogging but it wont go past 5psi

[CELison]

Well were you in limp mode after this happened? If you went into limp mode a year ago and it ran fine, that doesn't mean anything considering this is a new problem. What if any codes are you throwing? EGTs will cause hesitation, but if the whole car shakes that sounds like a misfire, a/f problem.

[Emilgevor]

I guess ill wait til scan on tuesday and upload logs and scan resulta

[DiscoPotato]

IIRC Blinking CEL = bad coil(s)

At least in my 02 1.8t that's what it meant.
Haven't had any issue's in my S with my coils.. knock on wood.

It means misfire

[Emilgevor]

I think i figured out what might be causing the issue. I got P1127 and P1129 codes today meaning MAF finally kicked the bucket. Idles poorly now. Car idles fine then jerks down 200-300 RPM then back to normal every 15-30 seconds.

[Emilgevor]

Finally got my issues fixed today. It had bad coild #3 and #1 was in its way out so i replaced both. Car runs like new again. Did some pulls tonight and it performed great. 19spike 15-16 hold

[epyx]

Thanks for posting an update. Still chasing down similar daemons in my S.

[Emilgevor]

Thanks for posting an update. Still chasing down similar daemons in my S.

My issue was that coil was not bad but going bad and it wouldnt trigger CEL unless i was stomping on it. As day went car started running worse and worse until yesterday I almost stalled with overheated cats. I remember pulling P0303 and P0301 codes basically meaning that my cylinder 1 and 3 were misfiring. I replaced ICMs because 1 and 3 are located on the same bank thinking that would fix the issue but it didnt. Tried swapping MAF but that didnt work ether so then i went and replaced 3 and 1 coils which took care of it. I will be replacing rest 4 coils pretty soon just to get that out of the way.
I went completely backwards in troubleshooting process but at the end i found out the issue.

Whats going on with your car?

[the dog]

Thanks for posting an update. Still chasing down similar daemons in my S.

+1