Misfire and Running Lean Codes
Hello everyone. New to this forum and I was wondering if you guys could help me with an issue I have been having. I am getting p0171, p0305 and p0306 codes. The truck is running really rough with poor acceleration and lots of shaking. So far I have replaced fuel filter, wires, spark plugs and ignition coil. I thought that maybe the injectors were bad, but I switched over the injectors from cylinder 1 and 2 and swapped them with 5 & 6 but I am still getting the cylinder 5 and 6 misfire. I've read that the p0171 code could be due to a vacuum leak, intake manifold gaskets, bad or dirty MAF, etc but what else could it be? Any ideas on the misfire codes? I am going to run a compression test tomorrow, but other than that I am stuck. Any help would be greatly appreciated.