[Tracey1212]

Okay, what I've got is a 2000 Lumina 3.1 engine problem. Here are the details:

1. The engine has 135,000 miles on it.
2. Other than oil, filter, gas filter, air filter, pvc, and battery replacements, not much has been done to the engine. It has run well so far, until now.
3. Recently, it began to idle slightly rough.
4. As the engine warms up to normal operating temp, the rough idle gets worse.
5. At peak operating temp, about mid dial, or about 180 F, the car often dies.
6. When the car is cold, it is posible to press the accelerator and watch the Tach move up nicely though the idle is slightly rough when cold.
7. When the car heats up, it is not easy to push the Tach past 2000 without the engine wanting to bog down and if you let off the pedal after hard acceleraton while parked, the engine may drop rpms so fast that it dies, sometimes.
8. With STP carb and inject cleaner added, 2 bottles to 1/2 tank or gas, the engine runs smoother.
9. No check engine light or codes present.
10. When the car heats up at idle to normal temp, the exhaust sounds puffy and you can feel the missing in the engine by the fact the exhaust comes out in lessor or greater puffs.
11. With the STP added, at least when the engine is cold at startup, the puffs are not present at all period! The engine exhaust is very smooth as it should be.

So.....whats the chance this performance problem is related to wires or plugs?

Gotta get this fixed fast. All ideas welcome!

Thank you in advance...