My GT lacks power and there is an odd smell...please help!

[sonyamon28]

[quote=bnaylor3400]It doesn't take much to damage a CAT convertor on a GM "W" body car whether it has a 3.1L V6 or 3800 Series II V6 with SC or without. One episode of poor gasoline can cause a misfire condition which cause the PCM to force the fuel injectors to go rich. When this occurs the internal CAT temperatures exceed 1200 degrees fahrenheit and causes a meltdown of the internal core which is turn is the clogging effect. Once the harm is done, it cannot be reversed and it will get worse with progressively more mileage. A simple bad spark plug or ignition wire can cause the CAT to go South.

Also an intake manifold leak of coolant into the combustion chamber can cause a similar problem. The excess coolant via the exhaust will run into the CAT convertor raising temperatures whereby causing a meltdown.

Hope the info helps.


Good news,
I got my Grand Prix back from the dealer. They replaced the CAT and it drives like a dream. Plenty of power! Thanks to every one for your help. Now all I gotta do is figure out why I get the low coolant message flashing on my dash......................

[BNaylor]

Thats good news Sonyamon28. Glad you got it fixed.

On the low coolant level, there is a coolant level sensor located on the right hand side (passenger) of the radiator about 3 inches below the filler neck and radiator cap. Sometimes the electrical connection to the sensor gets corrosion. Some people get the problem resolved by removing the sensor and cleaning it.

Also there may be air in the cooling system and all it needs is a bleeding.

To check the coolant level with engine cold and off, remove the radiator cap. Let the engine warm up until the thermostat opens. Then visually check the level at the filler neck. If low add a 50/50 mix of Dexcool until the level comes up. Replace radiator cap and then monitor the light.
Good luck!




Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials