I have a 2004 F150 Lariet 5.4, I have been getting a check engine light in with the following codes, P0316 (misfire on first 1000 rotations) P0308 (misfire on cyc 8) or P0174 (system to lean bank 2) but never both at the same time. So I started out cleaning my MAF sensor stayed off for about a week came back on with P0316 and p0308. so next I changed the spark plugs still was ideling rough. so then I changed the COPS (coils) same problem. Any ideas of what to do next I'am thinking about doing the injectors next but open to any other ideas Thanks

 

Check for vacuum leaks. Physically take the hoses off one at a time and take a close look for cracks. I had an Idle problem that was driving me crazy, throwing all different types of codes. All of my trouble shooting and experience kept pointing back to a vacuum leak problem. I looked at the vacuum lines while they were still attached and could not see any obvious issued with them.
It wasn't until I actually took them off, one ata a time, and took a closer look at them that I found the one with some cracks on one end, causing the vacuum leak and idle issue. I replaced that hose ( the one that attached to the back of the throttle body and goes to the passenger side valve cover) and the problem was solved.

Please post if/when you fix the problem.

Thanks,
David