Hi, I have a 2003 yukon with a 5.3L. I noticed that if I leave it in park and give it gas to get to between 900-1000 rpm, it runs alittle rough. I went to my buddy's house yesterday and he has a 2006 silverado with the same motor half the miles as mine. So we tried it with his. Same thing, idles smooth, runs fine in gear. But, when it is between 900-1000 it feels like it runs unbalanced. Anyone else notice this? If you don't mind, Try it on yours and let me know. Its not like it matters, it idles at 600rpm and when in gear it is always over the rough range. I was just curious if anyone else has the same issue, and if anyone knows what would cause it. Has new plugs, fuel and air filter, MAF was just cleaned, Throttle plate cleaned. I'm stumped.