Expert: Sean Halliday - 6/18/2009

Question
I have a 98 Mitsubishi Eclipse GST 5sp. The problem I am having is when I first start the car the RPM's rev up and down for a few minutes and then settle back where they are suppose to and then drives fine, but if I were to start it up and try to drive right away the car runs real choppy until the RPM's settle down. Any suggestions?

Thanks-Gary

Answer
This is a complex problem and could be many things.The EGR,mass air flow,vacuum leak,fuel filter,idle air control and so on.If the check engine light did not come on,its best to have the engine tested with a vacuum tester/diagnostic machine to see if there is a leak.Then you can go from there if the vacuum is ok.Other possibility is a leak at the intake manifold.This is best left to a shop if you have no equipment or experience to repair it.Its best to locate the exact part to replace as it is expensive to guess which one.Well worth the cost of a diagnostic at a shop as it will save you more on this car as they are a complex engine.