RMP's Shoot Up When In Park

malibu
engines
chevrolet
rpm
transmissions

#1

I have a 2000 Chevy Malibu (187K mi). Last year I was driving to work (24 mi one way) and noticed when I came to a stoplight the car seemed to be really hard to stop. When the light turned green and I let off the brake, it jumped forward pretty hard then continued on the way. Once I got to the parking lot and put it in to park, the RPM’s went WAY up to around 3K the second I put it in park.



It did this on and off for a week or so, one time getting so high in park I was scared to drive it. It was really sporadic. It quit for a day or two, then started again. I finally took it to a transmission shop…a national chain that is supposed to be good. After 2 weeks they still didn’t know what was wrong, charged me $500 for looking at it…didn’t fix ANYTHING and it’s been fine for almost a year. The only thing they charged me for was hooking it up to their computer and doing diagnostics. They said they were going to have someone test each wire one by one because it was showing a computer malfunction. However they did not actually do any work on the car. Just tests. I got it back and it worked fine for some reason.



Now it’s started to do it again. Rev’d really high, up to 2K when I put it in park last night…but today it’s been fine. What could this be, and who do I trust?


#2

You might have some gunk built up in the throttle body that is interfering with the throttle closing all the way. Does the gas pedal ever feel like it’s sticking in the closed position?


#3

Is the throttle electronic, or is it a cable? I thought this one was electronic, so the pedal would pretty much always feel the same…unless the mechanics of the pedal itself are at fault. That wouldn’t say anything about the throttle body, though.

Either way, throttle body gunk sounds like a good first look. Once clean, if it’s a cable, disconnect it (from the engine side) and make sure it’s not binding. It should push in and out smoothly, and with very little force required. This and the clutch cable are often overlooked until they cause problems.

Keep away from that national transmission chain you visited (pretty sure names are against forum rules). Talk to your friends, ask about local mechanics, who they use, and who they trust. I don’t think this has anything to do with your transmission, anyway.

Sometimes, it’s a dealer, and there’s no way around it apart from driving lots of miles. I know when I was living up North, the nearest dealer for my wife’s car was 400 miles away (bought it when I lived in the South, within 15 miles of 2 dealers). Not a trip I wanted to make - ever - but especially not with a car that was having troubles.

Chase