Ok all I am going nuts, my 88 F250 with 460 Has started pinging badly now that the temps are rising (summer) I am out of ideas. I have done cap, rotor, plugs, wires, and coil. timing is set to 10deg (spec) fuel filter and air filter are also new.
Any Ideas as to what I am missing?? It runs fine in the mornings but gets worse as the outside temps go up. If I run 91 octane fuel it all but stops pinging and generaly runs better.

 

i bet you have an emissions model with the cat converter eh? thats your most likely target if you do...plugged up cat. it creates high backpressure...notice a loss of power too?

 

Any codes?

 

A faulty pip sensor can cause a ping . Check the codes .
These pigs need high volume of fuel or they ping , if NO codes do a pressure and volume test on the intank lift pumps . Post results please

 

Yea it has a cat, I will check codes and let you all know.

 

ok if i did this right the koeo test showed a 1 1 all ok
the koer test showed a 4-1 and a 2-1 ??

 

21: Engine Coolant Temperature (ECT) Sensor Out Of Self Test Range
41: System Indicates Lean

The lean burn is the cause of your pinging, and I suspect the cause of the lean burn is a faulty Coolant Temperature Sensor telling the computer the engine is a lot hotter than it really is.

Here is what I'd do:
Get a new engine coolant temperature sensor and install it. Just remember that these trucks have two; one for the computer and one for the dash gauge. You'll want the one that has a two-pin connector on it. The dash sensor just has a single terminal pin.

Disconnect the battery for 15-30 minutes and drive it around for a while. If the pinging is gone - call it fixed. If the pinging is still there, pull the codes again and we'll go from there.

EDIT: Also get yourself a fuel pressure tester and check the fuel pressure. You should have 39.5 PSI key on engine off, a few PSI lower while idling, and 39.5 PSI if you snap the throttle wide open while running.

 

Thanks for the input, I will post back with results in a few days

 

Hey one of my friends has a 1992 f150 4.9 and it surges any ideas. i cleaned the throttle body and he put new plugs and wire cap and rotor O2 and the temp plug at the front of the motor. it runs fine when your going but when you stop at a light it surges bad and sometimes dies...?

 

Check your EGR Valve and also try spraying around intake area with carb cleaner if RPM increases...you have a Vacuum Leak