I could use some help. Just bought a 1997 XLT 4.6L for my son last week. Truck's got 91000 miles on it and is in great shape overall.
A couple of days ago we were driving out the freeway and noticed it was missing and pinging under load. The next day the check engine light came on. At speed it feels like one of the plugs isn't firing, but at idle it purrs like a kitten.
I've read the other posts on this forum and am heading off to Auto Zone this morning to get a code scan. Based on what I've read sounds like MAF might be the issue. Can anyone tell me where that's located? Thanks in advance!

 

The MAF sensor is located on the top of the air tube between the filter housing and the throttle body.

The sensor retaining screws need to be removed with a security Torx bit. I clean the sensor elements with spray brake cleaner, then gently dry them with compressed air.

Did you get any codes? They will point to what the computer has identified as a source of a problem.

Steve

 

I have a 95 F150 XLT with a 302ci and 137,000mi. It was doing the same as you describe in your thread. The code 172 was activated for EGO not switching (O2 sensor). Had it replaced and it runs fine now!

 

the missing sounds like an 02 sensor. All 4.6's ping--theres a number of things that can stop pinging. Try a new fuel filter, then fuel injector cleaner and a cleaning of the MAF.

 

so far i've replaced the plugs, wires, both front o2 sensors, had the injectors cleaned, removed/ cleaned the throttle body, removed/ cleaned the elbow behind the throttle body(egr ports looked like chracoal), seafoamed/ deepcreeped the motor, next i'm gonna replace the fuel pressure regulator(unless someone nows how to clean it). the good news is the pinging is gone, miss fire is gone but still got a check engine light due to low fuel rail pressure on both sides. wich it could of been the cause for the plugs going bad at 60,000 miles but i never got a light.

also FYI the check engine light will go out after 3 driving cycles(cold start, complete warm up, driving over 50 mph, cool down = 1 cycle), if the problems solved. if not, it will update after about 70 miles of driveing. then start flashing to draw your attention. if you disconnect the battery the light will go out but come back after 70 miles, or the problem happens sooner, due to the computer haveing a small back up battery thats independant of the vehicles electrical system.