Monky

Hi all,

My sti wagon v3 96 has a slight misfire when idling, you can feel the engine stuttering a little causing vibration, the revs are constant though and don't fluctuate.

When I pull off it also misses a little. Checked plugs they seem fine. It doesn't really effect the car in the later gears but the car is pretty laggy and is sporadic, sometimes quick other times lags and is slow. Wagon is standard apart from a hks filter and boost is also constant.

Thanks for any help.

Edit: above is most noticeable when cold but still a little hesitant when warm.

stevecrc

I had this problem on my 93 wrx this week, only missed at idlle and when driving at low revs but perfect when on boost. I replaced the coils and maf had new plugs two weeks ago and still done it,then remembered that i had run it very low on petrol last weekend. So i put two Forte gas treatments in the tank and within ten mins the missfire had gone

Monky

thanks for the reply, I run her low on fuel all the time why would this cause this problem even after filling up? Will certainly try it and report back! .

Monky

I've also noticed the hesitation is a lot more noticeable when cold on first starts, does this point to anything?

Thanks

saiklon

A dodgy fuel pump would cause similar symptoms. Have you got any way of checking your AFRs? They should go lean whenever it misfires if it's the fuel pump.

Monky

Yeah it's pretty much standard so no wide band, when I get a remap with standalone I'll get an uprated Walbro while i'm there. Only mods are a turbo back 3inch system and a HKS filter, don't plan to do anything else just standalone management, mapped on 98RON with a little more boost (1.2 bar) and that's all I have planned, meant to be my run around and being naughty already!

I thought it may be sensor related like MAF, have a new Lambda to go in as she has done just under 100,000 miles. Also need a new throttle position sensor but apart from that stumped! By the way Steve, tried some fuel treatment no different

Maybe the fact it's an import on 98RON is why it's not running quite right, hopefully a remap will shed some light when she goes on the dyno.

Cheers

demon dub

hi bud,reading your probs,sounds the same as mine(94sti wagon import)..intermiton misfire,slight bimp at idle,new plugs & new coil packs,still the same i can do 100 mile fine,then it can just drop to 3 clylinders good luck

Monky

Strange one, does yours literally run on 3 or did you mean it feels slow at times? Mine is sporadic, sometimes quick like an STi should be and other times it feels like a WRX, I have both so I can compare! The boost is consistant it just feels like it's loosing it somewhere, I'm going to check the up pipe and manifold for leaks but it's hard to hear leaks when you have a decat.

I haven't got round to fitting and mapping with stand alone yet but this should make a nice difference I'm hoping espeically as it's an import and used to higher octane. It does seem as if mine is running a little Rich, it pops and burbles quite a lot and feels boggy at times. Hopefully some good manangement and a dyno run will reveal some clues!