Misfire? Maybe spark plugs?

[dlskip]

Hi,

I'm reasonably new at all of this under the bonnet stuff and, not meaning to sound too stupid, was wondering if someone could help me with what I think is a mis-firing problem.

Sometimes, at around 2000-2500 rpm my R33 seems to momentarily splutter a little and then continue ok. It happens both accelerating and decelerating.

Is this symptom of a misfire?

If it is, what is the step-by-step process to check and (if needs be) replace my spark plugs? I've searched "misfire" and "spark plugs" on the forum but there's no step-by-step process for novices like me.

Or can my problem be a symptom of something else?

My 1993 R33 is basically stock. Just a 3.5" exhaust from the cat out.

I've only had it for 3 weeks and it's done 88000 kms so I had the timing belt, all other belts and water pump done. I don't know if the plugs have been replaced so that's what's got me think about them as the source of my problem.

I can't remember if I had the problem before the work was done because I was too busy giving it a bit of heavy right-foot work.

Anyway, any help would be greatly appreciated.

Thanks.

[raist60]

Strange that it should do it on acc. and dec. ?

Does the car idle smoothly? (Misfires due to plugs general give a shitty idle)

Does it do it on light throttle / medium throttle / full throt.?

Does it CONSTANTLY happen at 2000-2500 or is it random?

More info dude.

[GTS-t VSPEC]

dlskip,

If it was a misfire then I would normally expect it to be higher in the rev range 5-6000rpm, and it would normally be on acceleration only. Do you have and aftermarket computer?

If you've only had it 3 weeks then it should be under warranty, if you bought it from a yard, just ask them to have a look at it.

Otherwise my suggestion is to get it on a dyno, it should only take 1/2-1hour to determine what the problem is, and then you won't have to loose sleep over it.

Good luck.

See'ya:burnout:

[dlskip]

Thanks for the quick replies.

raist60:

The problem only happens on light to medium acceleration.

It otherwise idles beautifully.

It also only happens randomly, always between 2000-2500 rpm. It just kind of "hiccups", if you know what I mean.

GTS

[dlskip]

Thanks for the quick replies.

raist60:

The problem only happens on light to medium acceleration.

It otherwise idles beautifully.

It also only happens randomly, always between 2000-2500 rpm. It just kind of "hiccups", if you know what I mean.

GTS-t VSPEC:

I don't have an aftermarket computer.

I also didn't the car from a yard, so it looks like I'm on my own for this one.

In terms of dyno-testing, how much does it usually cost?

Thanks guys.

[hotsky]

i was also wondering about this same sort of thing....mine is fine while acc and decellerating, but just idleing it ''hicups'

however when idling it idles at about 1500-2000 is this to low....

when i had a service done...we incountered a rob which could be my prob...if so i need some advise

when we were changing the plugs...we changed all of them except the on right in the middle under the tubing or something, we were both pulling on the socket tool thing but could not budge the damn plug without snapping the plug......the guy put some sh*t on the plug and said hopefully next time this stuff would losen it up

[raist60]

See if you can swap an airflow meter with someone just to test. Only thing i can really think of atm

[Morgs]

If possible get the AFM checked out..

Also your fuel pump.. it could be fuel related.

[raist60]

Its possible that its fuel but unlikely as most fuel problems appear under load not light throttle.

[XXE-R32]

I dont know if this will help or not but when i first got my r32 the car yard filled it with normal feul and it was back firing and miss firing. When i put optimax and or BP premuim not a problem.

Dont know if that will help

[whistla]

check for leaks in your vacuum lines

i had a similar problem and found that a vacuum line had split off the intake manifold where it was t pieced to go to the computer