I have a 04 evo 8 just rebuilt 7k miles ago. Was running fine idling good then drove it yesterday car started to idle weird and loss of power then it would clear up about 2 mins later did it agine. Got it home waited a hour went out fired it up sounded like a Subaru no CEL. Runs lean at idle at dies
have Ben pointed to injectors just getting second opinions.
motor has
*built block Manley crank, Manley rods, wiseco pistons
*head gsc s2 cams, gsc springs retainers, stock valves, kiggle HLA
*fuel fic 1220cc injectors, walbro 400 Pump, aem fpr
*sparktec coil over plug set up
any help would be appreciated took a video won't let me upload it

 

Most likely a bad ignition coil or injector. Or possibly an issue with the COP harness.

 

I pulled it all apart cleaned all the connections didn't change anything. I sold my tactrix so can't data log. Probably just going to send the injectors off to get looked at.

 

Check the easy things first. Plugs and coils.

Pull the coil connectors one at a time to find out which cylinder is missing. Swap coils and see if it follows the coil. Change the plugs.

 

It sounds like there may be a bad connection in one of the gray connectors that plug into your wire harness on your Sparktech COP. Since each connector powers two coils, it would definitely cause the car to sound like a Subaru with only 2 cylinders firing. Check the connections on both sides of the COP and make sure the pins are all equally lined up inside the connector. One may be loose.

 

It won't attempt to idle on 2 cylinders that are firing at once, I doubt it would even do more than stutter when starting.

 

Car won't stay idling on its own will have to find someone to sit in the car to keep it running to pull the coil plugs. Thanks for all the replys

 

it wouldn't hurt but see if you can do a compression test. I'm having similar issues while getting a remote tune. Car ran fine prior.

Did a compression test and found zero compression on one cylinder. put a cap full of oil in that dead cylinder and reran the test. still 0.

Hopefully thats not your issue.

 

 

I had the same thing happen to me a couple months ago. It ended up being two bent valves in cylinder 1. I replaced all the valves and it's running strong now. Compression test or leak down test would be a good thing to try.

 

Do you recall what caused the valves to bend on your car?

 

I have no actual proof of anything happening, but the car came back home from a performance shop that way. The sad thing is that I had just had the head completely rebuilt and ended up having to do it again a few days later. It's possible that the shop put the timing belt on wrong and smacked the piston, but it was only the two intake valves on cylinder one. For the leak down test cylinder one would only hold 15psi with a continuous flow at 90psi from the compressor, so it was a pretty bad leak.

 

If the car is barely running, it's probably not valves, broken ring lands, or other engine issues that can cause that sound.
it sounds like something affecting more than one cylinder (or at least HOPEFULLY not valves ,etc, that is).
A comp check is really easy, though. May as well, just to give you peace of mind.