I have a MKIV GTI 1.8T that I'm having issues with surge/misfire.
Problem has been there for a while now but is getting worse.
It's not a constant problem it comes and goes. No codes what so ever.
At steady rpm it seems to miss fire and when coming to a stop sometimes it feels like it wants to die. When on freeway I hit the gas and it stays at 5 psi like in limp mode.
I let off and hit again and get full boost. I have a front mount with cold air intake, forge diverter valve, 3" down pipe and APR ecu I normally run 91 octane program. Have not yet replaced N75 valve (it's original). I was going to replace it with an Audi 034H valve. Any ideas on what my problem is?? PLEASE HELP!!!