Engine Ping - '00 XJ
 

Engine pings under load going up steep grades at various speeds. Have
been using 87 octane on a regular basis - pun intended - switching to
higher octane doesn't seem to make any difference.
Changing the air filter and plugs. What else should I be looking at?
Coil rail system thus no distributor or coil to mess with. I believe
that the timing is controlled by the PCM. Will I need to have the timing
checked/reset at the dealership? Thanks.

Steve