I'm pretty new to the turbocharged world and it would be greatly appreciated if you guys could help me out. I have a 2002 wrx with a motor from a 2004 wrx. It has roughly 50,000 miles on it.
My problem is that I have no boost, other than just wastegate pressure (about 7-8 psi) I think the car is in some sort of safe mode, as when I reset the computer it has normal boost (though has issues running well under full acceleration) There are no codes or CELs...I've ran it multiple times. After resetting the ECU, the car will run smooth under normal driving. However, if I get on the gas, at about 4000rpm the car stumbles a bit, seems to lag, then emits a small backfire. After that it feels like the powers back and it goes to normal boost range. However, after driving for awhile, the car seems to go in this "safe mode." Its incredibly irritating.
This weekend I plan on trying to change the spark plugs and see if that changes anything, but I have my doubts. Has anyone ever experienced anything like this? Any ideas, suggestions. Any help is greatly appreciated. Thanks guys!