rough idle


Asked by tatkins Jun 07, 2010 at 06:19 PM about the 1989 Pontiac Grand Am

Question type: Maintenance & Repair

I have had this car since 2007, and got it for a steal for only $800.00 with 80,000 miles on it. But, since I've had it, because  the previous owner let it sit up for a few years without being started, I have had challenges. Old dried out belts, bad alternator, and water pump, and basic tune up needed. I did all of the work myself, and when the car started to shut off while driving, I changed out the Crankcase sensor. However, the stalling problem is still going on, but it happens when I am at an intersection waiting for the light to change. All of the dash lights will come on and I would have to wait to restart the car. I've taken the car to three different repair shops around town, and on two occasions, I was told that it was the Ignition Control Module. I've changed that three times in the past five months at the recommendation of different mechanics... I've even changed the coils, the wire set, the spark plugs, all of the gaskets including the head/and header. I've changed the Idle Air Control, the Throttle Position Sensor, the M.A.P. sensor, the PVC Valve, the EGR (twice), the fuel filter, the fuel pump, and the fuel sending unit. Put a new muffler on. I've even changed out the manifold sensors, the coolant temp sensor. The engine does not overheat at all. I've changed the oil and redone the transmission gasket and changed the fluid as well. The strange thing is that I've been told that my Stalling/Rough idle condition is not electrical, but every time I work on something on the car and have to unplug the negative battery cable, when I plug the power to the battery back on, some of my tail and turn signal lights at the rear of the car stop working, and now my radio does not work... Oh...forgot to mention, I also changed out the Computer on the car, and the fuses according to the owners manual. Currently, with a slight adjustment of the Minimum Idle Speed, I've corrected the stalling problem...but, the engine shakes at idle, and you can feel it in the steering column and the cab. When the A/C is on it is even worse. And you can hear it as a constant clunk at the engine compartment, and a thudding sound out of the exhaust. If there is anyone out there that can direct me to correcting this problem, I would appreciate it. I am at my whits end and need some help. I've opened the oil fill hole to hear the valves and they are purring while the ending runs, and I can't pinpoint where the problem is... Please help

5 Answers


man sorry for the head ache sucks but since you done everything electrical have you gone the mechanical route yet injectors, throttle body, and on the fuel pump did you buy new or used-junk yard.. and did you replace fuel filter.. keep ur head up good luck

1 out of 1 people think this is helpful.

Hi, I too have a 2002 pontiac grand am with 300,000 km on it. I have had her since she was new and has always treated me well. lately, she has been giving me way way too many headaches. I had both windows in front fall into well, replaced battery, tires, intake manifold gasket, alternator and plugs and wires twice. Mine was using a lot of gas. It was finally diagnosed with a bad catalytic converter. So I have replaced it, not once, but twice in 6 months. Something is very wrong with my car. I have retired her to my garage where she will sit til someone wants to fix her. Im just sharing my story because I know, ive loved the grand am since 1987 when I had my first. Ive owned three in my life, am a woman and am 46 years old and I can honestly say, I have put alot of mileage on all three grand ams I have owned. So, Sir, if you can find out the problem, please post..I am curiuos and good luck to you!

1 out of 1 people think this is helpful.
Brent Bolz

Service bulletin ECU re-program my dealer did it for free, others charge $100

4 out of 4 people think this is helpful.
Loretta Goolsby

In 2012 while driving on the freeway my 2000 pontiac grand am would shut down. I replaced the crank shaft, this did not fix it, I replaced the cram shaft sensor, still did not fix it, I replaced the coil pack and fuel regulator still did not work. I was talking to a co-worker and replaced under the hood in the fuse box I replaced a plug in fuel switch a $8.00 part that fixed it. GM has a 2014 recall from 2004-2014 cars for this problem they should go back further people died from this.

1 out of 1 people think this is helpful.

This is such late post, Hope this helps in the future...... My problem believe it or not my Quad friends, It was my rear motor mount. 1988 Grand Am 2.3 Quad. it went flat on me with nothing to absorb the vibration. it may look good. i have went through all you have, Replacing basically everything. hope this helps you out. :-)

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