Pontiac Grand Prix Has No Power When Accelerating

I have a 2002 Pontiac Grand Prix. It does not have any get up and go. When I floor it, it bogs right down. I changed the fuel filter but it made it worse. I had it put on a scope at two different places and nothing came up because the check engine light is NOT on. Could it just need a tune up?

Hello. I think I can be of some help. A couple common things.
1- The fuel pressure should be checked to see if that is the cause of your problems.
2- Mass Airflow Sensors can also cause this problem but would have a code stored.
3-The most probable cause by reading your condition is that the catalytic converter is plugged. This is a very common problem. That also should have a check engine light with a code p0420, but not always.

The good news is that GM has a special policy adjustment for a failed catalytic converter. It is under warranty for 10 years or 120k miles. The special policy adjustment has a GM policy #05551. FYI, a catalytic converter replacement job at the dealer would normally cost $400-$700

It runs fine until i press gas then the car feel like can not go faster like does not open gas at all if i press gas gently gradually it go more until a limit. Also if i am driving at 30 mph w/ light or no acceleration it start a failure in the engine, is possible vacuum hoses, or gas regulator? No check engine light appear on dash is this because a possible broken light? 1999 Pontiac Grand Prix gtp 3.8 SC.

Trying to understand what you are describing, this may be a low fuel pressure problem caused by a plugged fuel filter or failing pump. This could also be a plugged catalytic converter. That gives the same feeling of a fuel pressure problem where you hit the gas and it will not accelerate. If by a "failure in the engine" you mean it is running bad, then the catalytic converter problem or bad spark plug wires causing an engine misfire could be your problem.

My 2003 Pontiac Grand Prix 3800 V6 will turn over, run for a couple of seconds and then shuts off. After about the 10th try it ran fine. My son says it has been difficult to start for a week or two.

Hello and welcome,. This could be 1 of several problems. You could have a fuel pressure problem(bad fuel pump, plugged filter), Leaking fuel pressure regulator causing a rich condition- which would stumble and chug before it dies, or you could have a theft system problem.

If after it starts and stall, leave key on and see if the security/theft light stays on or flashes-that would indicate a theft problem. While it is acting up, will need to check these things.

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