I've got a 03' w/ 6 spd, 90,000 miles. Mods w/ Superchip programmer, 4" ext., pyr/ boost gages and KN air filter. Lately when the motor sits idling it will start running rough, as if it is down a cyl. If I rest my foot on the accelerator pedal it will stop (not even moving the Tach). Idle is around 700 rpm. This situation happened a month ago and went away, but started again yesterday.
Anybody else had similar issue?

is there white smoke coming from your exhaust when it runs rough? My would run rough, it would shudder and I could feel it in the floor boards, and white smoke would puff out. It was my injectors.

Fuel filter first then check ballance rates all points toward injectors !

Not seein any white smoke and changed fuel filter 5k ago. I'll try changing the filter aqain (may have got some bad fuel hopefully), but it sure seems like a bad injector to me! I'll keep you posted.

Clean your MAF Sensor whilr you are at it, with that K&N, it might be oiled up and reading eroniously and causing a problem.

It won't cost nothing, and might fix it!

I added injector cleaner to a new tank of fuel and that seems to have done the trick. No more rough idle and fuel mileage improved! I also changed fuel filter aqain, but the old one looked fine. I appreciate the heads up on the MAF sensor, will clean that this wkend. i also appreciate the feedback guyz, will keep u posted if the issue returns.

Lube in the fuel cured a surge in my idle 15000 miles ago!

Good to hear it is getting better milage also