2000 SC2 accelerates on own and high idle
Gadget329
12-16-2012, 10:35 AM
Hello, I've had this problem for awhile and i can't figure it out and i really need to get my car fixed, i have a 2000 sc2 saturn DOHC 1.9 engine with just under 200k miles.
My problem is this, I recently purchased this car and was told it is in desperate need of a tune-up, being broke i decided to replace the cheapest parts first. I started with spark plugs, they are all gapped at 0.40 and all are new and the right ones for the car, ever since i changed the spark plugs the car has been idling rough (when i start it rpms go to 2500+ for about 10 seconds and drop to about 800-1100, when i shift into any gear it revs the rpms back up and they drop gradually). My other problems are that my car sounds like it is souped up and sounds like a rice rocket, when i put it in drive it starts to accelerate on its own and has reached around 40 mph at a gradual increase.
My uncle who was a mechanic said it could be the IAC, EGR or throttle position sensor, or cadilityc converter i replaced the IAC and it don't really seem to have helped much. i'm trying to gather as much advice as possible before i go out buying these expensive parts if i don't need them. i plan on doing all the work myself. any ideas what the problem could be?
Thank you.
My problem is this, I recently purchased this car and was told it is in desperate need of a tune-up, being broke i decided to replace the cheapest parts first. I started with spark plugs, they are all gapped at 0.40 and all are new and the right ones for the car, ever since i changed the spark plugs the car has been idling rough (when i start it rpms go to 2500+ for about 10 seconds and drop to about 800-1100, when i shift into any gear it revs the rpms back up and they drop gradually). My other problems are that my car sounds like it is souped up and sounds like a rice rocket, when i put it in drive it starts to accelerate on its own and has reached around 40 mph at a gradual increase.
My uncle who was a mechanic said it could be the IAC, EGR or throttle position sensor, or cadilityc converter i replaced the IAC and it don't really seem to have helped much. i'm trying to gather as much advice as possible before i go out buying these expensive parts if i don't need them. i plan on doing all the work myself. any ideas what the problem could be?
Thank you.
tech85
01-22-2013, 09:29 PM
your throttle could be getting stuck and/or your iac system should be checked
Ruley73
01-23-2013, 11:12 AM
Check the air intake clamps and make sure they are tight. Check the PCV hose that goes into the top of the intake manifold, it has a tendency to come off. Make sure the PCV valve is properly seated in the grommet. The metal lip that goes around the top of the PCV valve should not be exposed.
If these check out, the next time it goes to a high idle, put it in in neutral (or park if possible), shut off the engine and restart. If the idle returns to normal, it is most likely a bad throttle position sensor.
If these check out, the next time it goes to a high idle, put it in in neutral (or park if possible), shut off the engine and restart. If the idle returns to normal, it is most likely a bad throttle position sensor.
nathyrin
06-07-2013, 08:18 PM
Many times when you have a high idle its the TPS (Throttle positioning sensor.) I had this happen with my 00 SL2, was constantly fighting with acceleration with the brake. lol. It doesn't throw a code for the check engine light either.
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