I've spent a few days examining and testing the car, and I think I have some more serious issues at stake here...

The "pulse" in the turbo I feel/hear is occurring much lower-in some cases, at boost onset. I attempted a pass up a slight hill in 4th gear, and the turbo was surging and dropping repeatedly down as low as 3-4K. This can't be right.

Any further thoughts? Thanks again.

 

It could be one of three things: Fuel, Air, or Spark.

Does each coil fire? If yes, then it's not a spark issue.

Does boost hold steady? If not, you may have a vacuum leak.

Any fuel leaks you can smell?

 

I wish I knew more about engines here...I'm still learning, so bear with me.

Is there a correct way to check these things without ripping the entire engine apart? I know the boost does not hold steady...that's the entire problem. I don't even have a turbo gauge, but I can feel and hear it. How do I verify vacuum? How can I check the coils? I have smelled fuel from time to time, but very infrequently, and I could never verify that it was even coming from my car, and there are no leaks whatsoever.

Is it possible that the ECU isn't getting enough air and is cutting boost/timing back somehow? I am still putting back together the intake, and currently, the stock airbox is breathing engine compartment air through the hole that normally attaches to the snorkus.

I'd love to get to the bottom of this...thanks for the help.

 

the precat or "up-pipe" is getting restricted. I have seen a lot of these specially when octane booster is used continuesly as well as intake leak, etc. Replace it soon before it brakes your egt and do damage on your turbo.
good luck

 

I'll look into that for sure. I'm doing some work today, and I'm trying the grounding mod among other things, which I've heard is pretty good at getting rid of that hesitation too. We'll see. In any case, I'll go over the intake tract and make sure all is well there, and if things are still bad, that's next on the list.

 

i had the exact problem with my car a few weeks ago and it drove me nuts (i know how u feel).