Symptoms like a clogged cat

[Sig]

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

 

[christophero1973]

You already have the answer P0101 = BAD MAF. When you unplugged the MAF and nothing changed, that was your clue to replace the MAF, which explains the MPG drop.

 

[Sig]

Is there another way to test the MAF to be sure?

 

[GTPSHAWTY]

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

 

[Sig]

You already have the answer P0101 = BAD MAF. When you unplugged the MAF and nothing changed, that was your clue to replace the MAF, which explains the MPG drop.

I thought of you unplug it, it goes to a default setting?

 

[Sig]

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

I dont think it needs cleaned I'll check the vacuum line though

 

[Sig]

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

I checked the vacuum line it's clear

 

[Sig]

Any other ideas? What can the PVC cause?