i have a 2003 silverado 2500hd crew cab ls long bed 6.0l engine. At first i was getting p0101, p1133,p1153, p0171 p0174 until i changed out the fuel filter, the upstream 02 (before cat bank 1 and 2). There was hessitation and i would not want to idle. after changing those out, it idled fine between 650-700. I decided to change the MAF to get rid of the p0101 and it idles perfectly fine, drives fine but a few miles into it, i would get a p0171 code and p0174 Things ive already changed, fuel cap, fuel filter, 2 O2 sensors, MAF sensor. Checked for vaccumm leaks with carb cleaners at intake manifold, intake pipe, no change in RPM I went to change the PCV but on my truck it doesnt have a hose, it has a plastic pipe that goes to a nipple on the valve cover. What could the problem be? do i need to take it to the dealer to reflash?