When it comes to diagnosing a possible transmission problem, there's no much a DIyourself-er can do.
If your car has an ATF dipstick, you should start by making sure your level of ATF is right, and also that it is in good condition. When you do that make sure you follow the right procedure to check the level (transmission warm, shift in all gear at idle waiting for a few seconds in each, then come back to park and check level like you would with your oil).
You should check for trouble codes as well; it may help to pinpoint the problem(s).
A rough idle may be due to a vacuum leak, a defective sensor, wrong fuel pressure, possibly a plugged converter, defective PCV hose/valve, defective EGR valve, leaky valve, clogged injectors.
The car idling high when first started may be normal: since it's cold now, the car needs more gas to keep running and not stall (although 2000 rpm would be very high). However, once the engine is warm the car should idle at normal speed.
The loss of power and the exhaust problem make me think that you may want to start by making sure your converter is not plugged.
You could have too much back pressure resulting in some of the symptoms you describe.
A real diagnosic of the transmission will require a trip to the shop. Sorry.
Saturday, December 6th, 2008 AT 1:39 PM