1999 Grand Am GT 3.4L that does not want to stay running [Archive] - GrandAmGT.com Forum


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08-09-2008, 12:49 PM
I have a 1999 Grand am GT that the rpms will bounce up and down when the air conditioning is turned on and the idiot lights flash like the battery light, the ABS light, the brake light, the check tire pressure light. I have checked the tps, iac, maf, and egr. They are working like they are suppose to and I cleaned the iac and egr passages and the sensors. There is no check engine light on and there are no codes. Does anyone have any ideas?

10-19-2008, 08:19 PM
Ok, I'm going to add to the previous post as the issues have evolved and I can see them more clearly. For the last couple months I've been driving the '99 only once or twice a week because I bought a Harley for the commute with crazy gas prices (a little better lately). Winter is about here so I am going to have to drive it more often and it is acting more erattically lately so I need to find a fix soon. Hopefully I can keep your interest long enough to get some good ideas, solutions, etc...here goes. The '99 GAGT has about 103,000 miles...I don't beat it and I don't baby it. I try to pay attention to and it keep up with the maintenance pretty well.

It's 6am and I'm leaving for work, the car starts fine and idles fine, the check tire
pressure (this one is chronic) and sometimes the SES light is on, I put it in reverse, and things get weird. If I keep my foot on the brake everything seems fine. When I let off the brake and idle (used loosely) backwards down the driveway it feels as if the car does not want to stay running. The RPM's bounce up and down between 0 & 2500, almost stalling at times but managing to stay running. Near the end of the driveway or just in the street the Brake, ABS, and usually the SES lights come one and all the weird stuff ends until the car is started again. The other important pieces of information for that time it is acting
weird...the Brake and ABS lights (maybe others too) will flash on and off timed with the near stalls and higher R's...I hear a knocking noise, not like a combustion knock, but a knock like something is trying to move and is stuck/stripped and keeps trying to move, knocks about once a second I would guess. So this whole routine happened quicker a couple months ago...sometimes I would back five feet and the lights would come on and the weird ended...now it takes a lot longer.

I worked hard all day and I go to leave, the car starts fine and idles fine, the check tire pressure and sometimes the SES light is on, I put in in reverse and I get the same unusual performance as the morning. The exception is that it doesn't seem to clear as quickly. I sometimes in drive and get a block from work and it is still stuttering down the street. I don't notice in the morning but the speedometer seems to jump around also. Lately it has just plain stalled a couple times. After a stalls it seems to take a little extra time to start, but it always does. I sometimes pull over and stop to see what happens. Still in drive it idles fine, let off the brake and it starts stuttering again. While rolling, if I throw the transmission neutral, the speedometer goes to zero as fast as the needle will move and stay there until I put in drive again.

Things that have been checked, tried, or replaced. Replaced the air filter, pcv valve, and fuel filter. Cleaned the MAF sensor, EGR valve body, intake ports under the EGR, and anything else readily accessible. The throttle position sensor and idle air control motor have been checked and seem to be functioning properly. I'm not big on the idea of changing out parts until I find the one that fixes the problem. Most likely it would be the fifth thing changed and I would be out $600 or more.

Questions that I have... What the heck is the knocking noise that I sometimes think I can feel? Could it be something with the transmission/torque converter? Transmission was rebuilt at about 92,000 miles. Could a faulty wheel speed sensor be the problem? I have had issues with the front hub assemblies...both have been replaced twice. Since the last one about six months ago, I have had intermittent brake and ABS lights but it was only the lights until a few months ago. Would a leaky gasket under the EGR cause these things to happen? Could it be a cam or crank shaft position sensor? Could it be a faulty computer? I can't say for sure but it seems my gas mileage has gotten worse since this started.

Sorry for dribbling on about this but I'm trying to give as much detail as I know so someone can please help me solve this. As I browse the threads, I see that others have all the same things happen to their GA's that I have had or anticipate having so I know someone out there has a fix for this.

Thanks for your time...doug

gagt Mechanic
10-20-2008, 11:40 PM
there are alot of things that it could be. do you know what the ses light comes on for?
the problem dose go away though after you drive a bit?, its only on cold starts, or every time you turn your car off then on. main issue, SES LIGHT, that would probly help out alot, go to autozone.

10-21-2008, 09:54 AM
I had an issue once where the dash lights would flash occasionally for no apparent reason. I finally figured out it was a faulty ignition switch. This might explain the lights flashing during your stalling episodes. With the car running in park, try turning the key just a little to see if you can get it to act up. Don't try it like I did - on the highway, 65 mph, and I turned the key too far and locked the steering wheel......

10-21-2008, 11:22 AM
gagt Mechanic - I believe the code was an emissions code with EGR in it. I'll have it scanned again when the light is on. Would a faulty EGR valve or leaky gasket cause these things to be there only when in gear, moving, and right after startup? Does the valve have moving components that if not working right make enough noise for me to hear in the car? Ok, I know little about EGR's... It happens everytime the car is started. When colder (morning) it seems to clear a little quicker than lunch or after work. If I stop for gas and the car is warmed-up good, it is a real pain...lots of sputtering. I am starting to think it clears itself quicker when I go in reverse and even quicker when going fast in reverse. Thanks for the questions and thoughts.

cks20 - Thanks, I'll play with the ignition at low speed and see if I can get anything to happen. You have to tell the rest of the story on the locked steering going 65...

gagt Mechanic
10-21-2008, 12:14 PM
the egr can create a vacume leak that if bad enough can cause your car to run really lean, you said that the car surges in gear(rpms up and down) you could have a vacume leak. another issue could be a leaky injector or head gasket, giving the time could be head gasket, you could have coolant leaking into a cyl and washing it out. when cyl gets washed it may take a bit to get the compression back up. check your oil and see if it looks milky.

10-21-2008, 12:25 PM
I changed the oil a few weeks ago when I did the little lady's and it wasn't milky. I'll look under the cap and through the hole to see if it is. Not sure about the head gasket but I had the lower intake manifold gasket was changed at GM's expense at 66k so I hope it's not leaking in now. Mine was leaking out and I complained loudly so they paid me back for having it fixed at a dealer. Would a vacuum leak whatever it is connected to appear right after startup and then be better after the Brake and ABS lights come on? I'm clueless...maybe it's like five different thing happening at once.

Thanks again,


10-21-2008, 02:41 PM

The issues with ABS/etc can be caused by low voltage to the PCM. Pull off the boots on the wires and give them a really good cleaing and have the battery tested to make sure it is capable of holding up to the stresses of the upcoming winter!

gagt Mechanic
10-22-2008, 04:45 PM
so once the abs and brake lights turn on it turns normal? do the lights turn on once you start going about ten mph?

10-23-2008, 11:11 AM
Strange huh? Once the ABS and Brake lights come on and the knocking noise stops, it runs fine. I've experimented the last couple days...if I accelerate quickly in reverse right after startup I get the lights to come on right away. If I go slow in reverse or start moving in drive it taks a while of the stuttering and whatnot to get the lights to come on and run ok.

The oil appears to be clean and free of coolant. The battery cables look secure, free of corrosion, and properly greased. I have had a chance to have the battery load tested yet, but I think it is only 3 or 4 years old so hopefully that isn't the problem.

Thanks for the ideas guys and keep them coming if you can come up with other things to try or look at.


gagt Mechanic
10-24-2008, 11:13 PM
when it is running rough is the check eng light on or flashing? you could have a bad lifter. if you just rev the car in park or nutral, can you get it to run better, or only when driving?dose the sound come from under the valve covers, if so which one, or bothdo you get in your car and start driving, or do you let it warm up a bit first.

10-28-2008, 05:25 PM
Thanks again for the replies...sorry for the delay, I haven't checked back for a few days. When the car is cold, there is no noise in park or neutral. It's like everything is fine with the exception that the SES and usually Check Tire Pressure lights are on. When I put it in reverse, clunk, clunk clunk, that seems like it's right by the firewall not by the valves and it's pretty steady like it makes three clunks every two seconds. If I go quickly in reverse and then hit the brakes, the ABS and Brake lights come on and everything seems normal again...just like the old days.

Say I stop by the store and go back to my still warm care, when I start it I get the clunking in park and neutral too. It also likes to just kill which is just too much fun when sitting at a green light. The fast reverse and brake thing does not noticably help to get the ABS and Brake lights to come on. I have to sputter along with it threatening to kill at any time until it decides to correct itself.

What the heck is the clunking? Could the EGR or anything else like it make a clunking noise if not functioning properly? I'm starting to feel desperate like I need to take it to the dealership to be diagnosed and I don't like spending that much money on this car.

gagt Mechanic
10-28-2008, 10:49 PM
it sounds like you have manny problems. the clunk you describe sounds like a trans issue since it only happens in gear, the sputtering is a different issue, pos iac or mass airflow, brake and abs light sounds like a bad speed sensor, I dont know how mechanically inclined you are, but I would get it into a shop fairly soon.

11-06-2008, 02:06 PM
I think it is fixed now...it was multiple failure at once causing the strange symptoms. Two solenoids of the ABS unit were shorted out, the AC compressor clutch wasn't fully releasing causing not only horrible noises but voltage spikes also, there was one plug wire that was rubbing on metal which may or may not have been causing some issue, and the idle air control or throttle something (??) was out of adjustment. Main culprits were the ABS and AC so they are now with a fuse and disconnected...diagnosis, new wires, and readjustment of the intake component and I'm good enough for now for just over $300. LOL...they charged me for $17 in gas too because I basically dropped it off empty...my bad. Thanks for the comments and ideas.