Mitsubishi Repair: RE: Engine stall at idle - 2003 Eclipse GTS, engine stall, full scope

Question
In response to my earlier question: http://experts.about.com/q/Mitsubishi-Repair-824/Engine-stall-idle-2003.htm

My filter is about 10-12,000 miles old.  I'll look to get a new one and see if that does the trick.  I'm also up for my next 60K service, so hopefully they'll do a full scope on my on-board.  I forgot to mention though that the engine only stalls when warm.  When it's warm, the rpm levels are at a steady 5-600.  From there it'll dip down and stall when a vehicle passes by causing major vibrations.  Otherwise, it stays fairly steady.  

On one instance, a bus passed by and the rpms dipped down to about 200, and then rev'd right back up to idle without stalling after the bus passed.  It was very similar to how the engine reacts when you put the car in gear, and release the clutch up to the break point right before it stalls - then step back down on the clutch.  Does that make sense? Thanks

Answer
Sam: No it does not make sense to me, but then it is hard to know what is going on with your car; with me here and you where ever you are. I can only give ideas of what to check, you think it is due to the vibrations the other cars, truck or bus makes which messes with your car. I wonder if it is not that they pull the air away from your car's engine. I mean there is a lot of air moving around a car, truck or even bus as they zip down the road. You can feel this when say a large truck passes you on the freeway, it can pull your car to the truck and then that same air can push your car over too. The car stalls only when warm, means that something in your car gets warmed up and comes apart or such as a vaccum leak so if there is a small hole in a hose, the hose gets soft with being warm would open up more. As those hoses are made with rubber and so when cold they don't move as much. Still wonder if this is not a vaccum leak, how about that your idle speed is incorrect? How old are your stark plug wires? Have you had your emissions system components checked one or more might be bad or going bad. Could be your oxygen sensor is getting weak, there is a sensor called the Intake Air Temperature sensor so it could be bad. Those sensors all sent what is happening to them to the computer which then sets up the air/fuel mix. But if one sensor is weak or bad, the computer does not know this. And sets up things as it thinks everything is working right. So your car has it's problems. I wish I could help you more, but these are just ideas and maybe once you take your car in for that 60k service your shop will tell you that gal on the internet is just nuts. Would not be the first time for that said, I check my manuals, check things on the internet and then try to see what is going on. But without the car and being able to drive it; makes it hard. I can only just give you ideas. So I hope this helps you and good luck!