I have a 97 f150 with a4.6 engine. Has 240,000 km on it runs good but lacks power and when you accelerate it makes pinging sound bad. Used higher octane gas doesn't make difference. Changed sparkplugs coil packs plug wires, no difference. Mechanic said could be carbon build up in cylinders. Does this mean my engine needs rebuilt or is there anything else I could do to fix this. Any help and advice would be appreciated.

 

I'm assuming you checked for codes -all 3 types: present, pending and stored... even if no check engine light is present, it's a good place to start.

few things can be issue, MAF, EGR valve, EGR sensor, or even vacuum lines rotted or leaking among other things.

Post your findings and keep us updated! Good luck!