2002 Grand AM Chug on incline low MPG

I have a 2002 V6 3.4 L and it chugs on incline when you are going down the highway. It occassionally will chug when you first start to go as well. The MPG on it are also really low. I think somewhere around 15-18mpg. :screwy: We have changed the spark plugs and the wires, still having the problems. Anyone have an idea of what else it might be?

Oh yes, there are no lights but haven't checked the codes yet. :uhoh:

Welcome to AF.

Is thier any thing else you notice the car does?

I would say change the fuel filter and or check the fuel pressure.The test port is on the pass side of engine.
Should be 41-47psi. These filters do need changed pretty frequently.

We just changed the fuel filter in November, and it's maybe been driven 1000 miles since then, we went on a trip and that's when we reallly noticed the chug.

As for anything else it does, it does shift quite often, especially when on an incline, which is leading me to think it's a transmission problem. :naughty:

I would try and find out what your fuel pressure is as this might be your trouble.

How about when you turn left, does it rev or slip ?

If you have over 60K miles I'd change your transmssion fluid & filter.
Right now its probly low, so when you go up hill it looses pump pressure.

Btw-Their is no dip stick to check the fluid either.
Needs to be on a lift to remove the check plug located on the pass. side of the trans.

Let me know what you find out & Good Luck

Here's another thought. It could be your catalytic Converter. When they clog up, you'll have low MPG hard time driving the car like it has no power, transmission slipping and no lights come on on the dash. I can say this from experience. this is just a nother idea for you too look into. Good luck

Do any of you think it could be the fuel pump? I think so, hubby does not. I don't want to replace it if I don't have to but I wonder if it might be worth looking in to.

Hubby is a mechanic on leave with no tools, so this is driving him nuts not being able to figure out what the issue is. He is going to take it in to Checker today to see if they can pull any codes. I'll let you know what comes of that.

I don't think it would be the fuel pump. If it was you would be having more problems, such as stalling or not starting at all. Strange things do happen though.

Hello there, me again ;) Since we posted this, so much has gone wrong with the car.

It now has a P303 code? it was set because when you are accelerating uphill, or rather trying to "punch it", the tranny won't shift, it stops at 5 1/2 grand on the tach and the check engine soon light flashes. After you stop accelerating, the light turns off and the car chugs like it's not getting fuel. We've cleaned the master air flow sensors, checked for vacuum leaks, changed the spark plugs and wires, and still it's doing it. ANY advice please??

P303 is cylinder 3 misfire.

For some reason that cylinder likes to misfire.

Things to check would be wire harness for the injectors, could be a short.
Probly a good idea to test the injectors with a noid light,
or test thier resistance with an ohm meter to see if that is what's causing the misfire.

Also most of these models will red line at 5500 rpms. Unless its running great you wont get to 6000 rpms.

Though usually when the light flashes that means something is wrong and a dealer should look it over :rolleyes:
At least thats what the booklet that came in the cars glovebox says. :shakehead

And about poor MPG check/test the O2 sensors :grinyes:

The thing about the 5500 rpms is that it won't shift to another gear, it will stay in the same gear and just rev high and not go any faster...

it sounds to me like an injector problem they can be tested seperatly with a modis scanner. as for the mil light flashing that usually means it's a misfire problem.

The thing about the 5500 rpms is that it won't shift to another gear, it will stay in the same gear and just rev high and not go any faster...

Probly should have said that soooner !

It is going to probly need to goto a Trans or other qualified shop to diagnose the problem.

If you havent changed the trans filter & fliud that migth be something to try before you take it in.

Hope that helps.

http://www.roomsaccomodation.com/upload/roomsaccomodation/809/809_file/happy-easter-bunny-egg.gif

What is the reason for the p303 misfire code if it's in the tranny? Or is that a whole nother story? :)

Hi Viki. I'm new to this site and was looking for info on the same type problem. I own a 95 Grand Am and I think the Lock-up torque converter switch is not working. It acts like a manual trans. and not pushing in the clutch. Transmission keeps pulling when you try to slow down! Chug Chug

Mine misfires when it tries to kill the engine and will not shift correctly. Stays in lower gears (higher RPM less MPG)???

Sounds like the same problem. What do you think Xeroinfinity????

Love Cars

What is the reason for the p303 misfire code if it's in the tranny? Or is that a whole nother story?

p0303 is a cylinder #3 misfire very typical on GA's.
Could be ingintion system, plugs & wires, could be a bad coil, ignition module.
It can also be cuased by a bad fuel injector, a short in the injector wiring harness for #3 cyl, dirty or contaminated fuel.
Has nothing to do with the transmission :grinno:


Hi Viki. I'm new to this site and was looking for info on the same type problem. I own a 95 Grand Am and I think the Lock-up torque converter switch is not working. It acts like a manual trans. and not pushing in the clutch. Transmission keeps pulling when you try to slow down! Chug Chug

Mine misfires when it tries to kill the engine and will not shift correctly. Stays in lower gears (higher RPM less MPG)???

Sounds like the same problem. What do you think Xeroinfinity????

Love Cars

Your troubles could be a TCC solenoid which if bad usually makes the car die when slowing at stops because it doesnt disengage the torq converter.
This was a problem on early models not the 96 and up.

So NO these are not related problems in my opinion.

and Welcome to AF Love Cars.

ps I believe we have went over all of this on page 1 :grinyes:

Great, so I have more than one issue. Oh TGIF! Thanks!

Great, so I have more than one issue. Oh TGIF! Thanks!

Be sure and let me know what you find out.:banghead:

Love Cars, The 2002 uses a totally diferent trany , your car has problems with the TCC. Which I posted in your thread :)

Vicki7,
The 2002s do have a few problems but usually a fluid & filter will help chuging, which I think this is from a valve in the VB sticking. Cant realy tell from my house :grinno:

If a fluid & filter didnt help try some Seafoam trans cleaner, it is cheap and might help.

My 99' GT had some of those symptoms on hills and the above helped.

Good Luck

Where is the shift modulator located on the 2002 grand am?

The 03/06 coil pack is arching when you touch it with no signs of cracking. We tried switching the coil pack out and it's still arching. What can be causing that? We did an intake on it a while back, is it possible that something got squished in that process that's making it ground out and arch?

Where is the shift modulator located on the 2002 grand am?
If you are reffering to the Park/neutral safty switch it is on top of the trans, driverside. If you do a search in the N-body problems diagnosis you might find a thread I posted to test the PNSS.

The 03/06 coil pack is arching when you touch it with no signs of cracking. We tried switching the coil pack out and it's still arching. What can be causing that? We did an intake on it a while back, is it possible that something got squished in that process that's making it ground out and arch?

Yes,
If archs are coming from the coil then it is bad.
Though a wire could have been nicked when the LIM was done.
Especially the injector harness, this would cause misfires for sure!

but would that harness cause the misfire and the no shift at the high rpm and have no power when it isn't shifting or is it something wrong with the tranny and the harness or something in there???..

Hubby says it sounds like a vaccuum leak that's right behind the firewall but only when accelerating, sounds most high pitched when it should be shifting. ??

Mechanic talk...

So we are definately chasing two problems at once.

The plug wire is bad. I just changed them and have to change them again. That's what is causing the misfire. We're taking the car in to have the tranny serviced to see if that is what is causing the messed up shift in the car. They will also do a diagnostic test to see what else is wrong. Grand Am's are Pieces Of Sh**. I will never ever buy another one. Ever.

Good Luck

Most of the GA's are consistant in thier problems, meaning they all share simular problems throughout the line of different models.

Compared to other Makes & models I hav owned my 99" GA's are holding up rather well considering, with realy not many problems other then LIM & wheel hub sensors.

It's an exhaust problem! We took it in to have it diagnosed and the EGR valve is showing stuck open. There was something else, I can't remember off hand but it's showing as an exhaust problem. AGH!

Hi Vicki7, be glad its the EGR and not the transmission:grinyes:

Trans work is never cheap in a FWD car.

Hope this clears up your problem :thumbsup:

Ok, we got it back today and took it to an exhaust shop and they did a free diagnostic test. My Cat Converter is bad. That's what is causing the misfire codes and the chugging. Could've saved myself $150 on a tranny service if I would have known that first. LOL Oh well, at least now we're done chasing the problem ;)

Thier is an extended warranty on some 01-02 GA's.

I'll see if I can find the TSB.....

try looking here several hundred .... :shakehead
http://www-odi.nhtsa.dot.gov/cars/problems/tsb/tsbsearch.cfm

How do I find if it is under the extended warranty? I can't seem to figure that part out ;)

if your converter is bad then its covered under an 8yr 80k miles warranty

You never got the cat converter checked? I posted that as a possibility awhile ago for ya. Oh well. Either way, Justin is right about the warranty for the 8yr, 80,000 miles. you can find that in your emissions section under your warranty booklet that should have been in the car when you bought it ( if bought new). Once you get the cat changed you'll see a major difference in the car! Your G/a almost sounds like what i went through mine, when i had the same problem....

I was just telling DH yesterday that my cat was posted forever ago but he was being told by everyone it was the tranny. He is the mechanic for goodness sake! He said the cat was the next thing on the list. Dork! LOL Oh well, I have one smooth runnin tranny now ;)

Thanks for all the advice. I really miss the days when my hubby would say just bring the car in and he had all those handy machines to check it out, but since he felt the need to switch professions, maintenance has been KILLING us!

If you dont want to look through all those TSB's you can call a stealership and they can tell you if your exhaust was covered under the extended warranty, to 120k miles.
Due to Premature Cat failure because the insides were crumbling apart.

My local dealership said covered to 80,000 and I am well over that. UGH!

Might have just been a 2001 model issue with the cat then.
Might can a different dealer just to varify though.

I was just telling DH yesterday that my cat was posted forever ago but he was being told by everyone it was the tranny. He is the mechanic for goodness sake! He said the cat was the next thing on the list. Dork! LOL Oh well, I have one smooth runnin tranny now ;)

Thanks for all the advice. I really miss the days when my hubby would say just bring the car in and he had all those handy machines to check it out, but since he felt the need to switch professions, maintenance has been KILLING us!

Isn't stubborness great? :lol: , J/K I can sympathsize with you on the situation though, I went through the same thing with my Grand am, but the mechanics could not find anything wrong, that even when the trans began acting up, I was told everything was fine. I finally brought mine someplace else, to have a quick diagnosis of the problem as well as a comment of " I'm not sure how you were able to start the car let alone drive it.... it wouldn't have lasted much longer" Comforting thoughts I felt... :uhoh:

On to the warranty, as far as the TSB that XI is talking about with the extention to over 100k miles... you may want to try to fight it with when the car was built. Look on the sticker on the driverside door it will tell you the date when the car was built. If it was built in 2001 up until i think the begining of 2002 you have at least a fighting argument, since they didn't change the "weak" parts until halfway through the production of the 2002 model year. Thus the 2002.5 grand am's. right before i traded mine in they sent me an extention to a recall to now cover my car for the hazard switch ( which by then was already replaced) But some of the early model 02's had the same problems as the 01's. Just a thought to keep in mind, and you won't know until you try.

Mine was covered, according to the VIN from 2-10-02/2-18-2010 or 80,000. My car is at 93000 :(

Well at least your not going crazy trying to find the problem. Just trying to pay for the fix. (Don't know which is worse)!
Still chasing my tranny prob.
Good Luck

retracted, stupid question

neither a new pcm or a new cluster would change it.

Well looks like this dealership is getting $300 of my money ...Dangit!

Have your mileage checked thru the computer. My company owned 02Aztec cluster was damaged by a mechanic and had to go to a dealer to get replaced. Went in with 150,000mi and came back with 133,000. When I asked they said the computer said 133,000.

Sounds like what happened with Honda. Pushing the + or - 4% regulation. Let the odometer run 4% faster than actual to push cars out of warranty faster. They lost the law suit and had to pay. You may have fewer miles than you thought!

I'd say if all the manuf. were checked they all do it. If they give them 4% accuracy to play with they will use it to their advantage. The law was more than likely set with the older mechanical odometers. I'm sure the computer age made them alot more accurate.

Just wanted to update :)

After $235 for a new cat, we have found the issue. The cat converter. LOL It took a good $500 of guessing at which part was bad and found it today. I have my car and power and gas mileage back! Finally!

Thank you for all of your help!