I've done a lot of reading on this and I cannot pinpoint my issue maybe someone here can give me some insight. I have been getting a 3rd cylinder misfire consistently the last few times I drove the STi. It seems to come up during a cold start and the idle is a little rough. Also every now and then it will misfire on cylinders 1 3 & 4. I've replaced the plugs less than 15k miles ago and I've cleaned the maf. I've also checked for leaks, I'm just not sure where to go from here...I switched the coils around not too long ago and still got misfire on 3. Is there anything else I can do to narrow it down or anything I'm missing? Thanks in advance guys.
Swap the injectors around and see if they follow the injector. Might not be a bad idea to do a compression check too.
yea i agree with Integroid, do the compression test. That is how I found out I had a bust ring land on cyl 3. Because driving it with the misfires. I ended up with parts of coming apart and the plug damaged.
Agree, Compression check, Swap injectors, replace plugs depending on age and mileage of vehicle. I've heard of a TGV sticking slightly causing turbulence which caused a rough idle and miss fire. definitely recommend a compression/leak down
have you started getting this with the onset of the freezing temps? and it goes away after the car has warmed up?
Yeah it has been more frequent in the cooler weather. Also I was thinking this morning right after I got the car a friend of mine dropped a wrench and put a small hole in an oil pipe. I had to get the dealer to fix it because the timing cover had to be removed to get it on. Is there a possibility since it is tuned that they set it back to something that could cause the misfires?
Just curious, was it a stock injector? I know sidefeeds have always had weird issues like this. That is why I ended up going to topfeeds after my random misfire problems with sidefeeds.
Yeah stock yellow side feeds. I went with the same for now to save money but probably around the beginning of the year I'll be doing some upgrading then I'll change some things around. Thanks for the suggestion by the way boss. The car idles even rougher now that the shitty injector is on cyl 1. Does the firing order start on #1? Is that why it would run shitty? I was also recommended to go ahead and change the plugs again even though they aren't that old, my dad said that a couple of them are probably fouled now, the car backfired a few times on the way home after swapping the plug...and it was running pretty rough.
Just a quick update...Car run real good. Lol The idle is so smooth I wish I had figured this one out earlier. Thanks for all your help again guys.
cool man. im having a similar issue with my wrx. how many miles did you get on your plugs . im having to replace the plugs with 42k miles on them. seems weird.
Well the injectors basically fouled the plugs so I went one step colder. But they only had about 12k ish on them. Go a step colder I've noticed a huge difference....