2000 Eclipse Alternator Question

If the car runs fine at higher speed but just won't idle, it could be the mass air intake sensor. If not holding a normal idle means it stalls, this is what is could be. Not a cheap item either, make you wish it's the alternator.

Also could be a dirty throttle body too ...

I don't know. This all started when my battery went dead. I kind of think it's related. I think I'll check for bad grounds.

I have a 2001.

My battery went dead. Bought a new one, car started right up. Then the car would not idle at all, let off the gas pedal, stall. It was the mass air intake sensor. The dealer said it is very common for the Eclipse once the mileage is up there.

Over time a layer of sludge will build up in the throttle body. This would obviously cause the idle to drop as the air passage becomes clogged. On a computer controlled car the idle air opening is increased to compensate. When the battery is discharged (or disconnected) the computer forgets what it has learned and goes back to the setting for a shiny clean throttle body. The computer will eventually relearn but a better solution is to thoroughly clean the throttle bore and plate. Note: This may cause an overly high idle if at some time someone has manually readjusted the idle speed.

Clean with an oxygen sensor safe carburetor cleaner and a toothbrush. Make sure the toothbrush doesn't melt with the carb cleaner before sticking it into the throttle body.