Recently had the car in the shop with an idling problem (it wouldn't). Had the intake and turbo gaskets replace, and the idle improved considerably.

However, driving home, I noticed a significant hesitation at about 3500 RPM, and the boost would refuse to increase (and maybe drop a little) from where it happend to be, when the hesitation occured. The car will normally pull up to about 8lb. boost, but if it happened to be at 4 lb. when the car hesitated, it would go no further up.

Just to complicate things, occationally..it works just fine!

Engine is a relatively fresh street port, with a manual boost controller.

Any thoughts??
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Do you have a fuelcut defender? Because that sounds like too much boost.

 

8lbs.?

No, thats well within the capacity of the injectors and fuel pump. Its basically a track car, mild port, with a S5 turbo and boost controller that modifies the feedback pressure controlling boost. I'm told you're good up to at least 10lb. with the stock fuel supply system.

BTW, there is extra grounding to prevent the 'dreaded' 3800 rpm hesitation, and I have had a look through 'Search' to see if I could find something similar.

 

Check for a dead spot in the TPS. Also, check the Boost Sensor according to spec. And make sure there are no air leaks at the turbo inlet.

 

Check your ground. I've had this in a few rx7s and it fixed it. Sometimes it's just the battery negative cable is loose or corrosion.

 

I'll check the TPS and sensor next week. I was kind of leaning toward and air leak than a sensor failure as all was working fine prior to LIM and turbo gasket replacement.....but then the hesitation is rpm specific.

All seems good, no visible corrosion, but I'll pull the battery cable and give it a quick clean just in case.

Thanks guys