I have a 2002 grand prix gt with a 3.8 v6.
A couple of weeks ago I changed the upper and lower intake gaskets and the water pump. Everything ran fine for a week and then I descided to take a trip go STL, and on the way back at first it idled fine but when I went to pass a car on the interstate it would rev up really high but I wouldnt speed up very much and the check engine light would flash. Well I didn't want to tow it so I drove it 400 miles like this and my mpg just kept dropping, and eventually it started idling high (2500 rpm)
When it first started doing this I popped the hood and noticed the positive cable going to the alternator wasnt very tight and it was arching so I tightened it. Could this cause a bad ecu?
I rented a code reader from autozone and came up with these codes P0101, P0102, P0122.
I noticed something the other night the exhaust manifolds are glowing. I did some research and I think it could either be timing or the cat clogged. Could the timing being off cause it to idle high though?
I replaced the idle air control valve and checked the throttle position sensor and when I unplug the MAF nothing changes
Then I drilled a half inch hole in the exhaust before the cat and nothing changed