My 2001 F150 4.6L misses under load. There's no computer record and the dealer can find nothing wrong.
How many miles? My experience is that O2 sensors can cause this. If you have over 80k miles it is a possibility.
My 2001 F150 4.6L misses under load. There's no computer record and the dealer can find nothing wrong. __________________________________________________
A miss under load conditions is often the result of an insulation breakdown under the higher spark plug voltage needed at high manifold pressure. Wipe the dirt off of everything subjected to high voltage (plugs, boots, plug wires, coils, distributors, etc.) and inspect the parts for burning, cracking or other failure.
Sometimes you can see a voltage leak by duplicating the driving conditions: Place the truck's front bumper against a solid wall and have a friend run the engine under load while you look into the engine compartment for high voltage arcing. Do this in a totally dark area so you can see small arcs.
Wendy & John. ___________________________________________________
If it's pinging (more like a grinding sound) it's the MAF. I recently had this problem and it was caused by a small water leak around the thermostat. The water would run straight back and into the plug wells. I would wait until it cooled a bit to check under the hood and by then it was dry. Pull all your plug boots and check for moisture?
Been discussed here a lot. Not sure what the criteria is that the dealers use. I received a warning by mail telling me what to do if it blew. Post a question about 4.6 manifold warranty's and someone will help I suspect. I recall a lot of discussion and a lot of anger. Most weren't covered.