on way to work car gave 3 jerks, almost like it was backfireing, then was fine again. same night going home car started and ran fine for about 3 miles then started to jerk continuously and eventually kill. hooked up hand held diagnostics. no vacuum leaks. replaced map sensor and mass air flow sensor. ran fine for 3 days and check engine light didnt come back on. did running after work on 4th day and on the last stop it had a hard time starting back up.had made 3 other stops before the last one and no problems, but we were at the places for an hour or better between starting it back up. the last stop we were there only around 5 minutes when it gave us trouble. new plugs and wires , new coil.it doesnt happen all the time, only if the car is hot and shut off for just a short time. the diagnostic codes all read fine, fuel unit is fine. one person said possible catylitic converter insides melted and plugging up or crankshaft position sensor. the oxygen all read okay. any ideas or help would be appreciated. trying to avoid a huge shop bill. thanks in advance.
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2000 Buick LeSabre Question: what would cause the car to run great untill you turn it off then jerks & kills
Answer #1Randico February 16, 2013, 21:43Technician
You have a ICM (ignition control module) located on the top valve cover, I have seen these terminal barely making contact and doing exactly what you are experiencing so go to the ICM (this where the coil packs are) make sure the male and female are making good contact, Also during these model there use to be a debate crank or cam sensor, a failing cam sensor will also do this and will not code up
Replygoodguy, February 17, 2013, 11:02Master
I agree with #1
Replyhalfrack42, February 18, 2013, 04:37Rookie
icm was checked and was fine. took it to a shop for a full work up on diagnostics and they found it to be the mass air flow sensor, which we replaced 2 weeks prior. took back the bad one which had a warranty and the car seems to be running okay. the check engine light came back on but they said it was an oxygen sensor.