Say I take off in 2nd or 3rd from a roll. I get lots of sputtering and often a huge backfire. The whole car bogs down.
I can do the same 4th or 5th on a highway and there is no problem.
After the misfire or backfire, the engine soaks for 20 seconds as if it has been soaked in fuel even if I am trying to drive it normal. Fuel cut has been disabled in my tune. The tune is the same that it has always been. Nothing has changed.
I can run 2g timing or 1g timing. I can run it rich or lean...doesn't matter.
I recently changed the fuel filter, spark plugs, and wires with NGK/NGK Blues.
What on earth is going on? Compression is perfect across the board. This happens with full exhaust or with the downpipe open.