I have a 94 Legacy that starts to stumble at idle when in drive. It only does this when it has warmed up. Once you start driving it goes away. Another symptom or completely seperate issue is that since I bought the Legacy, it seems to have a very long shift modulation. Not a stutter, but it feels like it starts to shift and then a couple seconds later it kicks in gear and you start accelerating better. This phenomenon happens every time at between 30 and 45 MPH at normal driving. It does not happen with your foot in it. Timing belt, coolant sensor, alt, and water pump were replaced in the last 5k miles. My first notion is to do plugs wires and fuel filter. Is there anything else I should look at while I'm doing maintenance. I've seen post about the IAC, could this cause my problem? Where is it? Does the Legacy have a MAF sensor? I know on my Chvy the MAF causes all sorts of problems, is Subaru the same? I'm just trying to learn Subaru better. Love the way they drive and handle, now I want to dive in and start playing with what I got. Anything will help.

Front 02 sensor if not done in last 40k miles?

sounds like the band is geting worn check plugs \wires \coil for tracking

CEL finally came on. It was the IAC. Got some throttle body cleaner and cleaned it good. Problem solved. Thanks for the help.

the ecu send injector pulse for #1 cly thrugh the idle moter if its stuck the injector will not fire properly if idle moter is dissconected will run on 3