2003 Protege ES coasting issue

[wangwaffle]

I have an automatic (tiptronic, if it makes a different). when I take my foot off the gas while driving and the revs drop to about 1,200 rpm, the tach starts to spike up and down between ~1,200 to 2,200 rpm, and the car is jerky because of it. It goes away when I give it a little bit of gas or tap on the brakes, basically taking the revs out of that 1,200 range. Is it an engine issue, ECU, or transmission?

 

[Installshield 2]

sounds like the transaxle. Sorry, I'm not familiar with automatics (purposely avoided them all my life), but this sounds like a common issue when clutch packs and converters start to die. Have you maintained it? Older automatics need fluid changes as often as the engine...It could be ECU related, but very unlikely to be engine related unless there are noticeable problems in its power and driveability overall...

 

[wangwaffle]

I just got the car recently after wrecking my previous one So not really sure how to proceed for now.

 

[Installshield 2]

well if you've just purchased the car, and are unaware of its service history...might be a good idea to start with a transaxle fluid change. Most places can do it in under an hour or so, for relatively cheap. Again, i have no experience with auto's...but i've heard just changing fluid can smooth them out somewhat...might be all it needs. They also have shift cables or something that can need adjustment, all can be done during the fluid change by a decent service station.