Idle/boost Issue

[Tiral]

Hello, I'm sort of new to DSM's, worked on other peoples TSI's and GSX's with them. My mods list is upto date.

The Issue:

High idle (Around 1000-1100) low vacuum (Sits at 9-10) it has a rough higher idle, when I start it I need to keep giving it some gas to keep it from stalling then it holds idle and doesnt stall once it's warmed up, but still the rough 1100 idle with low Vac. When I give it a little gas at idle in neutral it goes to 18-20 vac where it should be. It's also running crazy rich.

When driving it, it drives ok but when you get on it a little and just start to build any boost it seems to hit fuel cut and fall on its face.

It is throwing 2 codes, MAF malfunction and knock. It's running super rich. I'm pretty sure its a vacuum leak and I've checked all the vacuum lines and they look good. I think I hear a Hiss noise from the TB area when it is idling so I replaced the intake elbow to TB and TB to intake mani gaskets and still hear it. The thing is the previous owner unplugged the EGR lines and left the Vac nipple uncovered on the EGR side and just left the EGR sitting there. I covered it and it didn't help. The thing I'm doing next is an EGR block off plate. Is it possible the EGR is stuck a little open or the gasket is kaput and it leaking vacuum and boost? It's near the TB where the Hiss is coming from.

Also the engine was rebuilt and has about 1400 miles on it, after the guy did that he let it sit for about 2 years and I'm guessing he left the EGR on there during the rebuild so its original.

I also do have the GM MAF and MAFT, so the leak would be after the MAF and like I said I changed all the gaskets and the intake mani gasket is fine. So basically is it possible a bad EGR/gasket could cause this problem?

Thanks for your time and ideas in advance, sorry for the long post just trying to give all the details.

 

[TALONTRAX]

Check for intake/boost leaks - anything leaking after the maf will cause similar problems . . .

 

[Tiral]

I think I figured it out. My SAF-C 2 is messing up and locks up on a screen. I bought it with the car and it was already installed. I checked the wireing and felt silly because I realized that the SAF-C changes the MAF reading and if it isn't working it is taking in that MAF reading and not sending it to the ECU so basically the ECU is freaking because it isn't getting anything from the MAF and adjusting the MAFT wont help because it still isn't making it past the SAF-C. Dur on my part.