I recently have purchased an 03 Evo 8 from a local Mitsu dealer. They sold it to me with low compression in cylinder 2. After fighting with them they finally put new pistons and rings in it and had the head gone over by a machine shop and put a new clutch in. Since I have gotten the car back it has run very well for the last 2 weeks or so. I have been running on wastegate pressure which seems to be right around 10 psi. I have been trying to put some miles on the car to break in the clutch and rings before getting the car tuned. All of a sudden one day I'm driving to work just cruising going around 40 mph the car would stumble like a dead miss and then next second be fine then the next second dead miss again over and over again for about 1/4 mile and then it cleared up. On my way home that same day it did it most of the way home.When it does happen I noticed my AEM Uego shows the afr pegging 10.0 when it misses. At this point I have installed a SpoolinUp COP setup and installed new bpr7es plugs gapped at .022". I have done a boost leak test and that is good as well. I'm unsure on the fuel pump in the car so I have a Walbro 255 on order to go in but I assume fuel pressure is fine considering when it misses the afr gauge goes dead rich. I have no check engine light or codes at all. Could this possibly be the EGR malfunctioning and opening randomly? At this point I am very frustrated and would really appreciate any help at all in a direction to go or other items to check.

 

anybody? anything?

 

Check your spark plug wires make sure the boots look good with no cracks. And pull the plugs to see if they are all uniform. Maybe clean your MAF with some MAF cleaner.