Ok so I have a 05 Evo 8 MR with a lot of mods done to the car. Long story short about a month ago my car started missing when I would be driving it. Almost like if you hit a dead spot in the tps sensor. The car would shake and miss violently. I would give it gas and the car would come out of it and start to drive normally. Then a month later it started to do it at idle, and now it is doing it and will not stop. It sounds like a Subaru and has no power. The car has no check engine lights. I was thinking maybe a boost leak or ignition issue. I know the car is getting fuel. Anyone experience this before?

 

If its indeed a miss, it is either missing spark or fuel--If fuel is good, then check plugs and coils--- sounds like a loose wire to a coil.. I had a similar prob with a COP kit--did the same thing, finally tracked it down to the wiring. Good Luck

 

I do have a coil on plug kit. It could definitely be that. Thanks for the advice.

 

also, since you have the plugs and coils out, do a compression check while you are in there, IF it's missing all the time now.

 

im kind of having the same problem, mine will sometimes hesitate like it's missing and then sound normal, it acts like it wants to die coming to a stop at a light, ive been told VTA BOVs can cause this but it's more often than not, could it be my BOV leaking??

 

what is your afr at idle when this issue occurs? are they stable in the stoich region or swinging?.... I am only referring to the issue when you experience it at idle.

Does this happen to you at idle when u turn on ur headlights as well?..... can you log your battery voltage when this happens?

 

BOVs make the car run super rich when you let off the gas. if you are letting off and taking the car out of gear to come to a stop, it may be loading up and wanting to die. without a wideband, it's hard to say. if it's stuck open, then you could be running lean. again, hard to tell. BOVs on a MAF car are never a good idea, despite people claiming it can be "tuned out".
do you have larger injectors? tuned?

 

My AF is right at 12.8. Which is why I was leaning towards plugs, coils, or compression. Which I hooenit isn't a compression issue

 

Do a compression, and if one of the cylinders is questionable then pull off the valve cover and inspect the valve springs. A broken valve spring will not allow the valve to seal properly and will throw ur afr's off..... I have had this issue on my car before and it sounded as you described "slobaru" rumble.
what valve springs do you have?....

 

I just have the stock valve springs.

 

does it consistently stay at 12.8?

running rich and a cylinder not firing does sound like an ignition issue. check the plugs first, then coils. sounds like you are on the right track.

 

that is exactly what I do when I come to a light most of the time, just throw it into neutral and coast, it'll seem fine when coming to a stop and then while sitting at the light it'll start to kind of sputter and drop down to 400-500 rpm range like its going to die, I have bigger injectors, I'm also running a 35r turbo, stock evo 9 BOV, my tuner that did my car had it on a richer tune since the motor is stock, of course I haven't had a tune in about 7 years, but it never use to do this when I first got everything done to the car back in '08, it's just started doing this more frequently in the last year, I have a wideband but the sensor is always going bad, I think it was mounted in a bad spot where moisture is getting on it and shortening the life of the sensor, that's for another day though

 

also you say BOV are not good for a MAF car, what would you use then, are you meaning you would want to recirculate the BOV rather than vta????

 

If the car was dying while coming to a stop but then return to normal I would say it could be the diverter valve. Since you have larger injectors, it really sounds like your BISS is out of adjustment. Mine used to do the same. The setting should be addressed any time you change injectors. Your tuner should have done this, but not all take the time.
And yes I just mean a recirculating valve is okay but one that vents to atmosphere makes MAF cars run poorly.

 

If it is 12.8 at idle or normal driving you probably have a boost leak as well.