valve ping noise

[Brokentoe]

My 4runner has 250,000 miles on it. other than the predetination or valve noise or whatever it is doing it is in excellant shape. I was wandering if it could be the knock sensor? It gets average gas milege 15/18 and plugs and cap and rotor have been replaced. I hapens when it is under a load. thanks Brent

 

[ovrrdrive]

On a motor with 250k on it, and pinging under load it's probably going to excess carbon buildup on the tops of the pistons causing the ping. I'd suggest a compression check.

You have done the obvious and tried high octane premium gas right?

I've never seen this problem be caused by the knock sensor unelss it was throwing a code on the engine light. I had a bad ping problem that ended up being fixed by a new rad, 180 degree tstat, and a new water pump. Evidently there was too much heat being retained in the head.

If you are having problems with carbon, a colder plug may help a little...

 

[04 sc V8]

If it's a 22re this is probably because of a stretched timing chain. Check your ignition timing.