Thread: Too many Damn problems

Originally Posted by neverstockgt

My 03 grand prix gt was recently in the shop for all new intake manifold, intake manifold gasket, thermostat, and a heater hose connector. When my friend picked it up to take to my house it died, in a 3 block span. The next day it died 4+ times going across town. Personally I dont know **** about cars and could really use the feedback, thanks guys.

If stock, check for a vacuum leak, possibly suspect poor installation of the upper intake manifold. Also there's a number of vacuum lines around the motor that could have dry rotted out by now.

Could also be a crank sensor or an ignition issue. Do you have any more details about when it dies?

Also could be fueling. Does it only die when you get on the gas? If so, it's a clogged fuel filter.

Originally Posted by neverstockgt

Before this shop I had a new cat converter put then a little after it went to this shop and now after it will kinda bog down before it dies, it start right back up no problem but when I take off it tries to die. Also have recently put a new fuel filter in.

If the car bogs or dies when under throttle it could either be a bad cat (bad on installation?) or still lack of fueling comes to mind. Fuel pump could be on its way out but I still think the cat is responsible here.

If you live in an area with no inspections just get a catless downpipe or some speed daddy headers off ebay for $200.

Originally Posted by neverstockgt

Well I took it to a muffler shop and it ran perfect for like 2 weeks after the cat was put in. And I was told there is an o2/oxygen sensor so it has to have one

The shop lies. 97-03 W-bodies don't need a rear 02 sensor (the one behind the cat). It'll throw a service engine soon light if you don't have one (p0141 if I recall correctly) but won't affect the way the car drives at all.

The front 02 sensor matters, but the rear one only measures catalyst efficiency.

Maf or crank sensor if it starts then dies. Any codes?

IIRC if your downstream o2 sensor is throwing a code, it will make the car dump a bunch of gas trying to compensate for the o2 not being there.....crappy MPG's. I would unplug the MAF then start the car to see if it stays running, if it does your MAF is probably dead. I would make the "shop" look at everything. If they find the issue, they pay since it ran fine before they screwed with it.

Is that city or highway or just a guess at both? I think people are seeing mid 20's being SC. I'm NA so mine will be different. I have an aftermarket cat and it is throwing a code and the gas mileage sucks right now.

Originally Posted by Below Average Joe

Is that city or highway or just a guess at both? I think people are seeing mid 20's being SC. I'm NA so mine will be different. I have an aftermarket cat and it is throwing a code and the gas mileage sucks right now.

eBay fouler lol mine sucked too and then I did that and see 22 city

can't get the o2 out....have tried 3 times. I have a fouler ready to go in..............Dan is just going to tune it out anyway

Originally Posted by Below Average Joe

can't get the o2 out....have tried 3 times. I have a fouler ready to go in..............Dan is just going to tune it out anyway

I need a smutty tune too since hpt can tune 06/07

Sure he can.....he's getting better. He has DHP and HPT

Originally Posted by hensleya1

The shop lies. 97-03 W-bodies don't need a rear 02 sensor (the one behind the cat). It'll throw a service engine soon light if you don't have one (p0141 if I recall correctly) but won't affect the way the car drives at all.

The front 02 sensor matters, but the rear one only measures catalyst efficiency.

This statement is only partly true. 97-00 don't need a rear o2 sensor, 01+ need an o2 sensor or the cat diagnostic test gets stuck on and the car will dump fuel. http://www.grandprixforums.net/threa...ou-should-know