Power surging problem...could it be the ECU?
 

Hey everyone. I've had posts in the main 2.0 turbo section on a boosting surge problem I was experiencing with my '02. Basically, at WOT in 3rd-5th, it hits around 3000-3500 rpms, and the car starts "pulsing"...you can hear the turbo spool and die, spool and die, spool and die, over and over, about twice a second in a constant pattern, and the acceleration suffers bigtime.

My local garage tried to diagnose it. They were sure it was a clogged cat causing bad back-pressure in the system. He said the turbo was pushing *25psi* at times...and holding it. My first thought was to pull the up-pipe and put a Helix in, and I did, resetting the ECU in the process.

No more problem.

Now, 500 or so miles later, it's back. It's not as bad...it seems to be a little higher in the rev range in 4th and 5th, and I can get on the gas a bit more, but it's much worse in 3rd.

I'm wondering if it's possible the ECU is to blame. I had re-set it a few times before the up-pipe, and it didn't do a thing. THis time it did, but it fell back into it again. FOr a while there, though, it was fine until it relearned it's pattern. Do you think it's possible the ECU had been re-flashed or otherwise altered to run higher boost with upgraded hardware that was removed before the car was sold to me, makingthe car act all strange now and pulling boost? Could something along those lines be the culprit? If so, would an AccessPort or other re-flash put me where I want?

I'd love any input you guys might have. Thanks!

I guess I was unclear there...let me try again.

How would a re-flashed ECU behave if it was done with mods that aren't on the car anymore? ex.->If the car had a full TBE/IC upgrade/VF34, and was flashed for that, and then the parts were pulled before I bought the car.

Would it be possible that the ECU was making the car overboost and then catching itself when it realized that something was wrong now?