Hey guys,

I have had some problems ever since I had my MAFS replaced... Right after it was replaced, around 3k RPMS in 2, 3, & 4th gear it stutters/surges. I brought it back to the place that put the MAFS in for me, and they had no idea what could be wrong. Someone please help, its crazy annoying. =(

 

No one has had this problem, or heard of it?

 

Did it do this before changing the MAF? If not and this is the only changed variable before the problem occured, tell them their part is junk and to replace it for you.

 

It's also possible the problem was present while your old MAF was there, but now that the MAF is good it's presenting itself. What RPM does it surge at? How old is your air filter? Are your spark plugs relatively new? Fuel filter in good shape? Primary O2 sensor doing alright? Does your N75 valve measure up to spec?

Another thing you should consider is running a VAG-COM scan to see if there are any stored fault codes, the kind of codes that won't trigger the check engine light.

 

Problem didn't start till after it was replaced, and they assure me that the MAFS if 100% good. Brought it back to them to have them look at it again, and now they say that my fuel PSI is at 68-70, and should be around 50-58. So they are telling me the fuel regulator is bad, does that make any sense to anyone? It only surges close to 3k rpms, filter is brand new, spark plugs brand new, fuel filter not sure, O2 brand new. How do I check to make sure the N75 valve is up to specs? Did the VAG-COM nothing stands out unfortunately... =/

 

I think the spec for our N75 valves is 20-30 ohms across the 2 pins.

If your fuel pressure is too high then that would certainly be an issue which can cause surging, especially at 68-70 psi. A stock car should run a 4bar fuel pressure regulator (58psi). Replacing the FPR is a simple thing to do, and it can be a pretty cheap part:
4.0bar Fuel Pressure Regulator [FPR4BAR] - $39.00 : USRT, Usually Sideways Rally Team

 

Thanks so much for the link, just put my order in for it!