Rep Power: 0

My 1998 Civic DX with 140k miles jerks HARD once when starting acceleration (e.g. going from coasting down a hill to driving on flat) or when moving from coasting to acceleration (e.g. cresting a hill and taking your foot off the gas). After the jerk, it drives pretty normally. It had a mild jerk, then I stored the car for a year, and it is a serious driveability issue.

The jerk seems to occur at a particular gas pedal position.

Maybe my TPS has a flat spot?

OR

Could this be a symptom of a worn clutch?

OR...?

In case its related: another issue appeared when it came out of storage, the car high-idles normally when warming up, but once its warmed up, it cycles between a high and low idle once a second. Very annoying, and probably bad for the engine.

Thanks a ton!

 
Rep Power: 217

Do you have any codes? The jerk could be from a stuck throttle plate or an out of adjustment throttle cable. I had an issue similar to that. Mine turned out to be that my throttle cable had WAY too much play. Adjusted it and all was well again. The fluctuating idle could be a dirty IAC valve.