I was sitting in a parking lot waiting for my wife the other day with my truck running and in park and I noticed it idling rough, it almost felt like a miss. Well since I had not noticed this before while sitting at red lights, I went ahead and put the truck in drive with my foot on the brake and the idle smoothed right out. I sat there for a while like that and the truck idle was smooth. I put it back in park, and within 30 seconds or so it started idling rough again. Repeated putting it in drive, it smoothed out and back in park, rough again.

I know there probably aren't a lot of people just sitting in park with their engine running, but has anyone else noticed this? Is it normal while in park to idle a little rough?

 

My '03 just started doing this as well. I have an aftermarket intake on it. Never did it before installing the intake.I tried resetting the computer and has not done it in 2 days. I noticed you have a K&N FIPK. Try reseting computer again and see what happens.

 

Actually, I have not had a chance to put the FIPK on my '03 yet, that was my old '00 that had it. My '03 is still stock.