I can't figure this out

[Filthy95talon]

My sh*t is messed up.
2g fwd Talon tsi, 9:1 6bolt (stock build), 20g, walbro 255 (rewired).
Other than massive unseen oil leaks, my car starts to sputter badly whenever I boost 3 to 5 psi+. I thought it was the crappy green top optical CAS, so I swapped it for a black top. I bought a new ICM. new wires, and fairly new plugs. I have a nice vaccum leak in my throttle body but the car idles at about 21 in of hg so it can't be causing that many problems. I recently replaced the mas. I have no data logger, wideband, or dsmlink. my computer is stock. I have some 780cc pte injectors, but they are not in right now, I have the 450s currently installed. when I install the 780s it still does the same thing. I've checked the fuel pressure at the rail and its right, but I don't have an aftermarket fpr.
I'm so worn out on figuring this car out... somebody help b4 I eat a bullet...
I JUST WANT TO DRIVE IT!
Basically I want to know what usually causes the symptoms I have. I also have the EGR blocked off and removed the evap.

 

[95blackGsTurbo]

First of all your I/C in your avatar is installed upside down. Next I would start going through the basic steps, boost leak test. The boost gauge reading ok has nothing to do with telling you whether or not you have a leak. Fix the problems you have before you try to tackle another.
IC Pipe Tester
Next what plugs did you get?(NGK BPR7ES) What are they gapped to?(.026"-.028") What is an ICM? How much boost were you trying to run. If you haven't taken the time to invest in a wideband, datalogger or some sort of tuning device you can expect problem. You need to start at the beginning. Check the basics and try to diagnose the problem. How did you check fuel pressure? These cars can't really be checked without an AFPR. Which you need with a 255lph fuel pump because you are already overrunning he stock regulator. Don't even think of installed the 780's til you have something to compensate for the fuel. Get back to use after you fix those things.

 

[talontsi18]

Like 95blackGsTurbo said start with one thing and move to the next till you fix all your problems. Do a boost leak check and fix the leaks, every leak makes a difference. You NEED a AFPR, all cars will 255 pumps need one, you are overunning the stock FPR. Check your timing with a timing light since you installed the new CAS. Projects take time to get them running right, just work through each problem.

 

[kneipperk]

i had a leak in the throttle body from the shaft seals and it was causing my car to jerk and buck like a SOB just like that at only a few psi of boost. did the seals and it solved the prob til my spark plugs went out a few days later, i was scared, thought it was something going wrong in my TB but it turned out just to be spark. both had the same symptoms. FIX YOUR BOOST LEAKS and then check your spark!
Oh yeah, my car idled just fine but as soon as you boost a few psi it would just sputter and jerk and felt like hittin a brick wall. i pressurised my system with my home made boost leak tester and poured soapy water and you can see/hear leaks. mine was only from the shaft seals... kinda hard to pinpoint it on the backside where the throttle is but i knew that was the only seal back there. i was amazed and what little i had left of my seals. forreal i will post a pic sometime but it was just the little metal ring with no seal or oring left it just got eatin over time

 

[Filthy95talon]

I have the same throttle body leak, I used the home made boost leak tester too and it was definately leaking around the throttle shaft.
I had an fpr installed b4, and when I jacked the fuel up with it, it just fell on its face. when I turned it down (like 20psi and lower), it would perform right but with the sputtering.
An ICM is an Ignition Control Module, and it was causing me to rev limit at 3500 to 4500, so I changed it and fixed that prob.
I do have the colder NGKs that you mentioned installed and they are fairly new, but that's not to say that they couldn't need changing.

I'm no master ASE mechanic, but I know way more than the basics and this car is not making sense. especially the part of the FPR. I had the 780's installed with an adjustable FPR and like I said push the pressure up, it falls on its face almost immediately... and then with it turned down, lower than stock, it would perform better but still sputter like it was starving for fuel.

I can honestly say that my problem seems like fuel, but everything with the fuel system was reading ok when I checked it and still had the probs.

First of all your I/C in your avatar is installed upside down.

yea I fixed it, I just haven't changed the pic.