pulsating idle and bucking during acceleration

[halffast1g]

During a cold start, the car runs great and I can punch the gas and everything is nice and crisp. As soon as the car idles down from the cold start, the idle starts to pulsate. The idle pulsates higher and higher until it goes over 1500rpm and starts fuel cutting. During any acceleration at all, the car bucks and will only make a few PSI of boost. Boost leak tested to 35+ PSI, so no leaks. I have ECMLINK tuning solution and the car will make 35 PSI (60mm turbo) on launch control, but will only make a few pounds of boost bucking and stuttering during any type of acceleration. What gives? I eliminated the coolant lines from water pipe to the FIAV and just looped the line on the FIAV. My buddy said I need to buy a blockoff plate, but I'm not sure this is causing my problem. Timing is on and double checked by an experienced DSM'er. Any thoughts?

91 tsi awd.

 

[BIRDCLAWTSi]

What are you using for a maf? Or are you sd?

 

[halffast1g]

This happens with both gm maf blowthrough setup and sd. I'm currently running SD as I thought it would cure everything, but the problem remains. Happens on gas and e85, injector settings in ecmlink are all appropriate

 

[boostneverlies]

I would start by blocking the fiav on the TB. There is a plug on the tb you can remove then bottom out a plunger

 

[halffast1g]

I would start by blocking the fiav on the TB. There is a plug on the tb you can remove then bottom out a plunger

I will certainly do that but I thought the fiav only controls the idle, do you think its possible that it is affecting the car when it moving too during acceleration?

 

[badbird]

Do you have a video of the said bucking or stuttering. Stuttering under boost is usually plugs or plug wires, I have had a stutter under boost that happen and had to figure it out while freaking out thinking it was something far worse. I also had a bucking problem once, bucking to me is much more violent then the stuttering, it was because I had to switch pins on the ecu in a 90 tsi, 6 and 14 I believe. A video would definitely help.

 

[c2ypt1c]

A video would definitely help.

a log would also be helpful...