surging when I let off the gas
ashleigh0473
10-05-2005, 12:42 PM
Im my 95 3.4L monte carlo, I can be doing about 35-40 mph and once I release the gas pendal it does this odd surging feeling almost like its going to quit, however, the motor is running fine. Could this be my catalytic converter? If it is, where is it located on the car? Please help
maxwedge
10-05-2005, 03:38 PM
Try cleaning the throttle body and remove the egr and clean that up too, for starters, any check engine lite? BTW not the cat.
Johnny Mark
10-07-2005, 05:26 AM
Im my 95 3.4L monte carlo, I can be doing about 35-40 mph and once I release the gas pendal it does this odd surging feeling almost like its going to quit, however, the motor is running fine. Could this be my catalytic converter? If it is, where is it located on the car? Please help
Hello Ashleigh, The surging my '95 Monte, 3.4L DOHC engine was experiencing, was most pronounced at start-up, but would continue to surge even after it had warmed up. At start-up, however, it was severe. It would always start, but would self-rev to about 3800 rpm's, then would drop off and stall. I might be able to keep it going for awhile if I fluctuated the accerator, then get it in gear to go, and hope that it didn't stall. When warm, at a stop-light, foot on brake, the engine would surge repeatedly, but not nearly as severe. I had the PCM changed out, but that wasn't it. I tested several sensors, and even changed out the IAC Valve (Idle Air Control "motor"), and that wasn't it either. It turned out to be an Intake Manifold vaccum leak, that I fixed by changing out the Upper Plenum, and Lower Manifold Gaskets. It's now running great!
You can easily check for Intake leaks by removing the Fuel Rail Cover plate, to expose the two-piece intake manifold(s), and spraying a mist of ether towards the mating surfaces. My engine started reving, as it was drawing in large amounts of air where it wasn't supposed to be. This was screwing up the PCM readings from the sensors, causing the PCM to decide that, due to the amount of air the engine was receiving, it needed more fuel. At the upper limit of the rev (3800 rpm), it would over compensate the other way, and the engine would stall, unless I fluctuated the accelerator.
Good Luck! Johnny Mark
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Hello Ashleigh, The surging my '95 Monte, 3.4L DOHC engine was experiencing, was most pronounced at start-up, but would continue to surge even after it had warmed up. At start-up, however, it was severe. It would always start, but would self-rev to about 3800 rpm's, then would drop off and stall. I might be able to keep it going for awhile if I fluctuated the accerator, then get it in gear to go, and hope that it didn't stall. When warm, at a stop-light, foot on brake, the engine would surge repeatedly, but not nearly as severe. I had the PCM changed out, but that wasn't it. I tested several sensors, and even changed out the IAC Valve (Idle Air Control "motor"), and that wasn't it either. It turned out to be an Intake Manifold vaccum leak, that I fixed by changing out the Upper Plenum, and Lower Manifold Gaskets. It's now running great!
You can easily check for Intake leaks by removing the Fuel Rail Cover plate, to expose the two-piece intake manifold(s), and spraying a mist of ether towards the mating surfaces. My engine started reving, as it was drawing in large amounts of air where it wasn't supposed to be. This was screwing up the PCM readings from the sensors, causing the PCM to decide that, due to the amount of air the engine was receiving, it needed more fuel. At the upper limit of the rev (3800 rpm), it would over compensate the other way, and the engine would stall, unless I fluctuated the accelerator.
Good Luck! Johnny Mark
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