89 f150 4x4 5.0 auto
Engine pinging under acceleration, do I need higher octane fuel, timing set, valve work....what?

 

My 88 F250 5.8L runs fine on any grade fuel. My 97 F250 5.8L work truck pings if I don't use mid grade fuel. I would try a higher octane and see if it helps.

 

more info is needed.

check wires, plugs, dist. cap, fuel condition, clogged exhaust.

 

clogged or simply restrictive exhaust....I never put the two together, but my truck has not pinged since I put the dual exhaust on it 3 years ago.

Ditto on the plugs, wires and cap & rotor. Check all the basic tune up stuff.

 

The EGR valve if clogged up and stuck in the open position can also cause pinging. Have you pulled your codes?

 

all plugs,wire cap,rotor, etc are relativly new.
exhaust from cat back is new, cat has been cleaned out.
no codes using the jumper wire.

 

Check your timing then. If it's right, then you are probably looking at carbon deposits on the valves.