Missing All Of A Sudden :(

[nizmo_freek]

Well took my car for a drive tonight and it was feeling rather slow, so i gave it a bit of gas and all of a sudden i get heaps of popping and ratling out the exhaust,im guessing its missing??? It coffs and popps from about 4000rpm right up to the rev limiter, and it feels very very slow, the car has never had a miss since ive owned it (about a year and a half).My mods are 3"exhaust,intercooler,pod and gtr fuel pump, i installed the gtr fuel pump about 3weeks ago and the car has never missed a beat untill tonight , ive taking out all the plugs and they all seem fine (there ngk iridiums, about a year old) they are a little bit brown tho, so what else can i check??

The car was also boosting very high when it was missing, about 0.8-0.9bar (it normally holds 0.7bar right to redline)

Cheers

[Craved]

sounds like excess air flow protection .. otherwise called a boost cut

check your intake system. mine did this when my restrictive filter fell off..

[HR-32]

check your vacuum hoses........intercooler piping?

Edited April 25, 2006 by HR-32

[Luke 34GTT]

What spark plug gap are you running? If it has only started when boosting higher, i would try reducing your gaps from 1.1 down to say .8mm etc (thats if u havent already)

[nizmo_freek]

Im running ngk iridium plugs that are gapped to 0.8 (i bought them like that brand new), i didnt raise the boost or anything (i dont have a boost controller) but the boost spiked to 0.8-09bar (boost is always at 0.7bar right to redline) only when it was missfiring, all the vacuum hose and intercooler pipes/joiners seem fine

[nizmo_freek]

bump, any more help?

[Fixxxer]

It seem like the usual missfiring issues.

Was it a cold night compared to when u normally drive? I've found boost does go up in colder weather. Turn boost down to the usual 0.7 bar and see if it does it, if it doesn't missfire on 0.7bar then it sounds like a usual spark plug/coils missfire. I had iridiums (that were mega worn though) and mine used to missfire like mad at not much more than stock boost. I changed to normal copper NGK's at 0.8mm and the miss totally disappeared (apart from a slight miss at idle, which is another story).

Fixxxer

[TTT]

tape up your coil packs with electrical tape.

[nizmo_freek]

Ok,put all the coils (all covered and sealed in silicon) back into the car today after work and went for a drive at about 6pm, the car still had the exact same problem and was very very surgey,but it "seemed" like it wasnt popping and farting as much as before,so i drove back home very dissapointed and decided to reset my ecu,took the car for a bit of a thrash and the problem had completly dissapered ,what the hell is wrong with my car???

Im stumped lol

[nizmo_freek]

Took the car for a drive at 9pm and it was driving awsome for about 20mins then everything turned to ****,started popping and farting again,it even does it when im on about 3/4 throttle (and it feels really slow and non responsive even when im driving slow around town), so i came home and reset the ecu once again which fixed the problem completly,i guess its going start popping and farting tommorow just to piss me off lol.IMO i think its something to do with the ecu (althought that dosent explain why it was going fine for 3weeks then all of a sudden started having problems), either a boost cut or a fuel cut or something (as it completly clears when you reset the ecu) Any more ideas??im starting to get desperate

[insu]

Ideas:

Is this all on the same batch of fuel? Could be a bad batch.

Hard to say otherwise, maybe you should wait till it starts doing it and get it on a dyno and check out your AFR's, boost, power, duty cycle, fuel pressure?

[nizmo_freek]

Right, finally i have some good news , i took the car for a drive last nite and came home as soon as it was going bung, so i came home turned the car off and unplugged the oxygen sensor,went for a drive and the problem was completly fixed,was driving around for over an 1hr 1/2 trying to get it to fault, but it ran awsome, so the problem turns out to be the oxygen sensor, i will put a new one in next week and let you know if it does actually fix the problem

Cheers for all the help people