Grand Prix dragging running sluggish til warm

Another question regarding my good ol' grand prix...hopefully the same person that helped me before with the coolant loss issue can help.

At any rate my car is in the shop right now and they have tried several things to eliminate a particular problem which is my car drags when accelerating it is a 6 cylinder but takes off like a 4 cylinder, like it is dragging a trailer with bricks on it and it kind of gets better as I drive it more but not really, it just kind of loss it guts....I know that tried a replacing a coil of some sort then some ignition module so they are stumped, anyone have a guess?

is the Check engine light on? if so, pull the codes and post them here.

What year and model Grand Prix to include engine size. If a 2001 - 2002 you may have a bad CAT convertor.

hey Bob, just a note, he just had an intake job done, and it's an '02 3100.

hey Bob, just a note, he just had an intake job done, and it's an '02 3100.

Thanks for the heads up Rich. Yeah, good ole 3.1/3.4 intake gasket problems. Knowing that I would defintely have an exhaust backpressure test run to see if the CAT clogged or went South. The coolant leaking internally from the gaskets does not burn off completely in the combustion chamber and winds up in the exhaust/CAT convertor causing the temperatures to exceed 1200 degress F. Screws over the CAT in the process....called melt down.

Plus if he was under 120K miles on the odometer he would qualify for a new CAT from GM because the 2001 - 2002 Grand Prixs were delivered with flaky CATs.

is the Check engine light on? if so, pull the codes and post them here.


Yes, the check engine light is on, they are not receiving any codes when they plug her in...nothing, not one code is coming back, it is stating all clear and fine?????????

Thanks for the heads up Rich. Yeah, good ole 3.1/3.4 intake gasket problems. Knowing that I would defintely have an exhaust backpressure test run to see if the CAT clogged or went South. The coolant leaking internally from the gaskets does not burn off completely in the combustion chamber and winds up in the exhaust/CAT convertor causing the temperatures to exceed 1200 degress F. Screws over the CAT in the process....called melt down.

Plus if he was under 120K miles on the odometer he would qualify for a new CAT from GM because the 2001 - 2002 Grand Prixs were delivered with flaky CATs.
I guess the boys at the shop have just begun the exhaust backpressure test just as I was calling them to tell them about your suggestion...the car has over 120k so looks like I won't be getting any freebees from GM.

Stay tuned, no telling what will happen next...thanks for the suggestions.

Plus I don't want to disappoint anyone but I am not a he but a blonde haired blue eyed she, that knows just enough to be dangerous about cars....I knew enough to find a automotive forum to find out how to get-r-done...lol
Thanks for the info at any rate.

IF the check engine light is on, there MUST be a code stored. I would say it's either a plugged up catalytic converter from the coolant or a bad sensor. I was leaning toward a mucked up oxygen sensor, but you said it runs better when it warms up, which is opposite of what a bad oxygen sensor normally does.

Plus I don't want to disappoint anyone but I am not a he but a blonde haired blue eyed she, that knows just enough to be dangerous about cars....I knew enough to find a automotive forum to find out how to get-r-done...lol
Thanks for the info at any rate.

Sorry about that. I'll try to be less gender specific. :lol2:

Hopefully, you'll get it resolved.

Sorry, we didn't mean to call you a he, and there's nothing wrong with a blue eyed blonde she, especially if you know about and are interested in cars.

Sorry, we didn't mean to call you a he, and there's nothing wrong with a blue eyed blonde she, especially if you know about and are interested in cars.


No problems with the he thing....I just didn't want it to seem like I was deceiving anyone. :icon16: :icon16:


The car is just perfect...after they fixed the CAT issue..thanks a lot for everything both of you.