The surging or how I tried describing it to people "hitting a rev limiter" it almost sounded like that. like a fuel cutoff or something. Things I tried - (omg nightmare trying to pinpoint this problem)
First thing- checked fuel pressure, good.
Fuel pressure regulator- good. changed for testing. nothing.
Maf- good. changed for testing, nothing.
Fuel pump - hangar ended up being messed up internally, car would shut off randomly with no fuel pressure. ended up stock ground on the hangar couldn't keep up with the new DW fuel pump, so I took it out and put a racetronix 340 with a new hangar/sender and called it a day. didnt fix it.
Tried multiple coils, ignition modules, plugs and wires, gapped the plugs a few different ways. same stuff.
Injector harness (hell I was getting desperate) nothin.
So between this problem and having the trans destroy my thrust bearing I was pretty upset. Almost sold the car but stuck it out and just didnt beat on it, because it only happened at WOT!
The plugs were a give away but I didn't know any better. The tip was like a crusty white color....looked very similar to detonation, but I knew I was getting fuel and the readings on the scanmaster were telling me I was actually running a little on the rich side, WTF?
mind you, of course I didnt bother checking for oil in the up pipe or checking the turbo, that couldnt be it...its still making boost! so i thought....
Then recently I changed the valve springs. Same damn thing. really pissed after that. I readjusted the cam sensor. same thing. I went over EVERYTHING except taking out the injectors and flowing them (which I almost did)
then, a couple weeks after the valve spring change, thinking man I messed up my cam, its wiped (but no slivers on the magnetic plug) I saw the light, or smoke....lol
The car started to smoke after warming up a couple minutes. and it got progressively worse QUICKLY (weeks period) until the car was a fog MACHINE!! ok, theres a problem. checked turbo. destroyed. oil inside my uppipe and even going back towards the maf. everything was covered. oops!
Put a ta-49 on the car, car runs brand new. a week after I installed the new turbo there was still some smoke, nothing coming from turbo though. Pulled the intercooler, I must have drained (yes, tilted my intercooler upside down and drained) about a pint of oil out of it. Washed it thoroughly. No more smoke.
Hope this helps the OP, kind of a long story but that was my adventure for months.
...this gremlin seems to have alot of faces....took me a while to get the courage to keep it pinned on a motor with only a few hundred miles on it. It is a soft rev limiter type of surge.
