Thread: My First GTP experience - Won't rev past 2k - HELP!

Hey everyone, long time lurker, first time poster here. I buy and sell cars, have been for years and worked on my fair share of new and old GM products. Earlier Today i purchased a 2003 Grand Prix GTP from a recently widowed friend of mine. Knew nothing about the car been sitting for about a year. $300.
Formalities out of the way, I got it started up and it idles on it own will not rev past 1.8k-2k and causes horrible shaking.
In gear the car can barely pull itself in to the driveway. I've checked all the normal stuff, plugs, wires, injectors, MAF, vacuum leaks, etc. Everything checks out. I even disabled the injectors (with HPT) one-by-one to see if there's a problematic cylinder, no problems there.
The only DTC I've experienced is P0300 (random misfire of course). And the only abnormality I've noticed is highly fluctuating STFT, somwhere between -5 to -25 rapidly. O2 sensor seems to be responding appropriately.
Is there something I'm missing???

I'm about to head to the store and pick up some fuel system cleaner, maybe that'll help.
Thanks, Levi.

Originally Posted by Fivefingerdeathpunch

Check the plugs and wires. See how strong the spark is at the coils.

Originally Posted by thetastywarrior

checked all the normal stuff.. plugs, wires, injectors, MAF, vacuum leaks, etc. Everything checks out.

Originally Posted by Fivefingerdeathpunch

the exhaust is completely clogged at the cat converter and not allowing it to rev...

And this was the problem, Cat was clogged. Just cut the exhaust gutted it and welded it back together. Good as new.