Low revs misfire
 

My 1995 STi import has got a really annoying fault. When driving in traffic on low throttle openings (below 3,000 rpm) the engine keeps cutting out/misfiring for a split second. As soon as I give it some revs it clears up. The lower the throttle opening (eg coasting at low revs) the worse the problem is, and it is also worse with extra people in the car. I have just had all 4 coil-packs replaced but it has made no difference. No fault codes are showing when plugged in to a diagnostic machine. Has anyone got any ideas?

P.S. Sorry for posting a link to the Ken Block thing earlier! Didn't know the world and his dog were sick of it...

Have you changed plugs and leads?

All 4 plugs have been changed. Didn't know there were any leads – I thought it had coil-packs instead (I'm not very good with spanners! Pay other people to wield them for me...).

hiya mate, if you cant find fault with just plugging in diagnostics, try and find a good diagnostics/tuning place that has got a plug in unit for your diagnostics port which stores faults when you are using your car but dont show up when you go to a garage..


steve

have you got a VTA dump valve? they supposedly cause similar problems

I get this as well with my 96 V3 Sti import drives me mad, does yours literally cut out or just small misfires? Mine doesn't cut out but you can feel the blips of misfire through the throttle at low RPM. What fuel are you using and what mods, has the car been remapped? Fuel plays a big part with the imports which I've found out, are you using any octane booster as this made mine even worse. With Vpower it's the least stuttery I've found so I out it down to needing a remap!

It virtually cuts out but just for a split second - the whole car jolts. As soon as I apply throttle it clears. I generally use Optimax or equivalent, but not always.

Could it be over-boosting due to the cold damp weather..? :wonder:

Lambda Sensor
 

Hi

i have just put up a post regarding my lambda sensor on an sti 02. I had a similar problem with my sti V4 and it turned out to be the lambda sensor - no ecu codes etc but when replaced sorted the problem.

On the other hand my 02 Sti has the ecu light on and the code says its the same sensor. It still drives but at low revs its very jerky - maybe its your sensor playing up, just a thought

Mark

When my O2 sensor went it was as you described so I would be inclined to agree with mk2rallydriver. I found it was much worse when it was cold, once it warmed up it seemed a lot better. Interestingly there was no CEL light so it cost me to have it diagnosed, I bought a genuine Subaru part but others use a universal with no problems and these are a lot cheaper.