I am working on a 1988 F-150 lariat 5.0 L. The following have been checked and/or replaced. plugs, wires (wires are in correct order), cap, rotor, dist and module, coil, no codes showing, TPS, IAC, cleaned throttle body, all filters, good fuel pressure, power flushed injectors, ignition timing 10 degrees spout unplugged around 25 degrees spout in, MAP. Nothing dragging, I can push the truck by hand easily. Not running hot at all.

Any more ideas ?

 

whats the L you put after 5.0?

 

Litre

 

Did you do a compression check on the engine. The pinging sounds like you might have carbon build up on the top of the piston or vavles. Id check the compression first. How many miles are on the engine.

 

How is the exhaust system on your truck. I had an e150 in work that did the same thing and the catalytic converter was blocked partially.