Ok, so for a while now my truck has had a miss/studder at around 1200rpm. It's not everyday but it's there sometimes and it's annoying. I took it to rockin s and it passed buzz but #4 injector failed contribution. He replaced it and for about a day it seemed better, again it doesn't do it everyday. The next day it showed itself again, I would have called rocky but I'm a one chance kinda guy, if you don't fix it the first time I'm not goin back. So now I'm at a loss, it's a very sight miss at idle but it's pretty bad at 11-1300, but no where else does it do it in the rpm range. Already replaced the uvch, gpm, fuel filter and oil. Please help me figure this out!! 147k miles