Hi folks, I am brand spanking new here and wondering if I could please ask for help. I have a couple ideas, but it's not my car and I don't want to waste her money.
My MIL (Mother in law) has a 2001 Grand Am with the V6 engine. The car only has 40,000 miles on it. Lately, it has begun to (as very best I can tell) have an idle issue where once the car warms up (and this is where I am stuck), it will idle fine but every 2 minutes or so (almost rhythmic, but I didn't actually time it), the RPMs will start to oscillate and sometimes kill the motor due to the wild swings. It only appears to do this in neutral (I drove it and it drove fine), but she said it happened while she was in gear, like stopped at the bank or a long red light.
There are no codes, the SES light is not illuminated, I disconnected the battery and reset the ECM, examined all the connectors I could find (with the battery disconnected), and looked at the front 3 spark plugs (I was ambushed with this and wasn't fully prepared)(plugs looked fine and consistent with each other), and added some high-buck fuel treatment, and then I ran out of time. Overall, the car is in good shape.
My first thinking was (due to the rhythmic occurence) maybe the EGR pintle is stuck, but then I learned about some folks having issues with IAC solenoids.
In exchange for a little affirmation, I promise to pay it forward. I am normally loathe to join a board just to get an answer, but she don't live real close to me and I could sure use the help.
Thanks, -bryan
ETA- I have a scan tool that shows accelerator position, and the readings are smooth and as they should be. I measured the fuel pressure at the Schrader valve and it is steady at ~45 PSI while running, and rises about 3 PSI while it is acting up, then (provided it don't kill) goes back to ~45 when the idle smooths out again.
My MIL (Mother in law) has a 2001 Grand Am with the V6 engine. The car only has 40,000 miles on it. Lately, it has begun to (as very best I can tell) have an idle issue where once the car warms up (and this is where I am stuck), it will idle fine but every 2 minutes or so (almost rhythmic, but I didn't actually time it), the RPMs will start to oscillate and sometimes kill the motor due to the wild swings. It only appears to do this in neutral (I drove it and it drove fine), but she said it happened while she was in gear, like stopped at the bank or a long red light.
There are no codes, the SES light is not illuminated, I disconnected the battery and reset the ECM, examined all the connectors I could find (with the battery disconnected), and looked at the front 3 spark plugs (I was ambushed with this and wasn't fully prepared)(plugs looked fine and consistent with each other), and added some high-buck fuel treatment, and then I ran out of time. Overall, the car is in good shape.
My first thinking was (due to the rhythmic occurence) maybe the EGR pintle is stuck, but then I learned about some folks having issues with IAC solenoids.
In exchange for a little affirmation, I promise to pay it forward. I am normally loathe to join a board just to get an answer, but she don't live real close to me and I could sure use the help.
Thanks, -bryan
ETA- I have a scan tool that shows accelerator position, and the readings are smooth and as they should be. I measured the fuel pressure at the Schrader valve and it is steady at ~45 PSI while running, and rises about 3 PSI while it is acting up, then (provided it don't kill) goes back to ~45 when the idle smooths out again.
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