I have a 2002 f150 with 4.6 has 226k on it. I'm trying to fix a rough engine performance. I'm suspecting maf sensor and o2 sensors are faulty but how can I test and know for sure before I switch parts out. I have a dmm and scan tool but not sure what the reading are suppose to be. If someone could let me know what tests to do and what is an acceptable reading that would help me also thank you

 

Are you getting any codes on the scan tool?

 

There are YT videos to show how to test MAF etc. Easier to learn from a video than trying to explain in text.

Neither of those necessarily translate to rough engine performance. Check for codes. Run a vacuum gauge test on your engine to find any possible problems.

Is maintenance up to date ? (plugs/filters etc )