Thread: Symptoms like a clogged cat

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

think the throttle body needs to be cleaned?? or maybe that vacuum line leaving the tb may be clogged up