so the other day i am driving my car and all the sudden the car starts to misfire horribly. it sounds like an sti the cel starts flashing. so i put the car in neutral and look for a place to pull off.. the car dies so i start it up again(still sounds like an sti) at this point im thinking there goes number 4.... the car dies again so i refire it and it runs perfectly soo i putt the car home...


at this point im thinking it cant be blown so i go buy some brand new ngk bkr7e and replace all the plugs,, all look gapped correcty and all are pretty black except # 4 it is white on the tip and black around the base... start the car up and it still is running on 3 cylinders.. so i call my buddy ssblkstealth who tunes for trifecta.. he come out we start the car it stumbles at first then runs fine with no cel so we take it around the block about 5 mins in it starts to misfire again he is data logging so maybe we can find whats going on... havent heard back on that yet this was all friday..

soo today im thinking its either injectors or coils so i got out to check them but the car runs fine take it around the block still fine....

what do you guys think it could be im kinda scared it will do this again but i can find the problem if it runs fine when i go to check things... mods are in sig an dhave all been on the car for about 30k

thanks!!!

 

anyone?

 

Bump

 

flashing cel is a recurring misfire in a short amount of time. the fact that the car does run normally sometimes says its not blown. but theres definitely an ignition problem. you may be right about the coils. i don't know the part numbers of the ngks but if you're using a one step colder plug try moving to a step 2 colder. also are you using any additives when you fill up? it could be something in the gas causing the plug to not ignite correctly. any way of checking kr while driving??

 

The ngks are one step colder and I am going to seafoam the car to day and clean the air filter to see if that will help thanks

 

Check crank sensor may be loose or bad connection

 

Ok thanks I'll check that out

 

Mine does that too sometimes exept no flashing cel, it says engine power reduced and sounds its running on 2 cylinders, i start it a couple times and its good idk what wrong

 

yea idk what the heck is going on im about to go check some more things just dont want to be in the middle of rush hour and this thing take a crap on me

 

Yeah exept mine only does that when i decide to go full throttle sometimes, pisses me off when it does that

 

easy, test swap the 1 and 4 coil. drive around the block, if its still 4 misfiring swap the 4 and 1 injectors, drive around the block. if after swaping both coil, injector and plugs the misfire is in #4 you have a mechanical engine issue with cylinder 4, either cracked sleeve, failed ring, something like that. but rule out plug, coil and injector first.

 

was going to do all of this but now the car is running fine went for a 15 min drive and did pulls in 2nd and 3rd gear no misfire at all... thats what i dont understand i cant test anything if it wont mess up when i try to test it.. maybe it was jsut a fluke or bad fuel idk.. ill update if it messes up again

 

Yeah mine happens every once and awhile, the engine prob sayin nooo you cant go full throttle hahahhahaha

 

lol yup silly cobalts!!

 

+1. you can rule out plugs if they are all fairly new and gapped properly. swap the coils, if the problem moves then it's a bad coil. if the problem stays, it's not a coil nor a plug, swap injectors.

also, #4 is at the end of the fuel rail, and a white plug usually indicates a burnt plug aka high combustion temps. Lean = High temps, so it may be a fueling issue indeed. While your looking into fuel issues (if you have to go this far) check your fuel pressure. there's g2 be a schreider valve somewhere, i haven't had the need to check my fuel pressure yet but if there is one somewhere that'll help rule out fuel pump issues.

where did you last fill up? I've had a bad tank of gas **** my car up good. The thing ran like *****, engine power reduced, got new gas problem solved but my 3 week old plugs were burnt to crap.

::EDIT:: i totally missed the post where you said the problem is gone, heh. man, what a waste of 10 minutes of typing! jk. glad to hear all is well.

 

I suspect #4 Fuel Injector.

Unless I'm mistaken, white at the tip means the plug was fireing lean.
If the coil was bad, the plug would be all fouled from fuel that wasnt burnt,
due to not fireing correctly

Check for codes, you should have a P304,
The codes will tell you wich cylinder is misfireing
P300 = Multiple
P301 = 1
P302 = 2
P303 = 3
P304 = 4
P305 = 5 (Not Applicable our cars)
P306 = 6 (Not Applicable our cars)
P307 = 7 (Not Applicable our cars)
P308 = 8 (Not Applicable our cars)

 

After you determine which cylinder is misfiring, swap in a coil from a "good" cylinder and see if the misfire jumps to the one you swapped it with. If it doesn't jump, then you'll probably want to inspect the harness for that particular coil pack. I had a very similar problem on my car and it ended up being a frayed wire contacting the block. Every time it would make contact it'd misfire. This explained why sometimes the car would run fine, but others it would be a total nightmare.

 

thanks for all of the replys and i have drove the car for two days now with no problems this is what i dont understand !!the only thing i have done is seafoam the car.... when the misfire was happening the cel would only come on when driving... at idle(car still misfiring) it would go away also no code on accessory mode... so i had no way to read a code because there was no code to read... because of that i could never find out what cylinder had the misfire so swapping coils and injectors would have been useless.. for some reason the car went lean i still dont know the cause.. i am thinking about getting a trifecta tune soon maybe this will help

 

The only time I had a cel for misfiring was at the track for the first time when I almost stalled it off the line. Car bucked back to life and the cel blinked and said I had misfired. Never happened since then. Hopefully your problem was a fluke. Good to hear its running normally, though swap coils as stated above if it happens again and you'll narrow it down quickly.

 

i was going to suggest changing the fuel filter, but it looks like the car is ok. keep it in mind if it acts up.

which method did you use to seafoam?

 

will do!! just did the fuel and the vacuum line none in the oil..