That sounds like classic TPS failure. If my fuzzy memory serves, the TPS should provide a voltage range of somewhere around 1.5V (throttle closed) to 3.7V (throttle open). (Of course those numbers may be off a bit but you get the idea.)
If it's providing the wrong voltages then the computer gets confused and doesn't provide the correct air/fuel mixture.
In the shop manual (possibly also Hanes/Chiltons?) there is a very easy test with a voltmeter for checking the TPS. If the voltage reading you get is wrong, then the TPS is bad.
The non-philips screws are probably a lame (see below) effort to discourage backyard mechanics from doing it themselves.
I haven't looked at my own TPS (though I think I plan to buy one to replace it shortly) but I suspect they're Torx screws. If so, you can pick up a set of Torx screwdrivers most anywhere that sells hand tools (Sears, etc.).
In my GC, the engine exhibits heavy pinging on 87oct fuel, and noticeable pinging with 89oct fuel -- I'd have to mix in about 10 gallons of premium to get the pinging to stop. Assuming I don't have heavy carbon buildup (which I doubt since I always use Chevron and have tried various carbon-cleaning products to no avail), I'm thinking the TPS may be giving wrong readings, making the computer provide a leaner mixture (too little fuel). In your case, sounds like the computer is providing a richer mixture (too much fuel).
Cape Canaveral, Florida
2005 Jeep Grand Cherokee Laredo 4.7L
2005 Dodge Durango SLT 4.7L
Last edited by Intrepidjeep; 11-24-2003 at 03:01 PM..