Speed density. Or are you still running a MAF?

 

did you only replace the coilpacks or the 4 plugs are also new?

 

Is it a misfire or like a stutter? I had a similar issue where the car runs fine until 5k rpm and then there's was a stutter/misfire. Turns out the cam sensor was loose and what make the car temporarily read 0 rpm once it hit 5k

 

I remember a guy who posted about his pcv (recirc?)hose coming off and getting oil into the cam sensor plug that caused problems.
also check the ground wire in that area. that thing is brittle

 

What does the car have as far as upgrades? Aftermarket parts? Even a hose coming off for emission like the common hose that comes off from the fuel regulator!

 

What injectors are you running?
After the misfile does it continue at higher RPMs >4000?

 

Yes we got the issue fixed it was the fuel pump was starting to go. The evos fuel pump runs on 10v when idling then moves onto 12v under load which is why it could rev to 8000rpm no problem when stationary. Take the car down a hill and see if it will rev past 4000rpm as the fuel pump does not have to work as hard.

 

nice diag

 

Not to hijack -- but this stutter problem sounds exactly like what I've been experiencing off and on the last two years. What do you mean by the cam sensor? The crank position sensor or is there another one? Thanks.

Edit: For the OP -- I don't have misfires on cylinder 3, but it's always my ugliest spark plug when I change them. Someone here said they look like that one runs a little lean. I'm not good at reading the plugs. Saw that you got it fixed -- good job.

 

Hi, I also experienced some stutter when accelerating.
One of the spark plugs got somehow as bit loose, replaced all of them to be on the safe side and the stutter was gone for good.

 

My cam sensor looked fine. A little oil weepage, but that's just an O-ring replacement or RTV the cover there. But it was solid.

Definitely had the loose plug happen before. I guess it might have happened again, but I did check them last summer. I have a head gasket job coming up (other thread), but I'll take a look at everything in cylinder 3, check the threads, see if that's where my head gasket blew out (minor blowout, but still needs addressing).