You guys are right , it definitely is ping ( detonation problem)
While I was at Costco , they only have 87 and 91 Octane , so I had about 1/3 tank of 87 left before refueling , toped up with 91 . Running back on the highway about 2 miles didn't seem to change anything but maybe too soon to tell.
[/B] I think I'll need to reverse engineer the Catch Can to elliminate it as a possible problem ( I belive the problem started after I installed it . The only problem is I cut the boots to get it off the OEM hose , I'll need to reorder (Damn)
Here is an excerpt from this web page[B] Read #2 EGR,
A DOZEN WAYS TO PREVENT DETONATION
1. Try a higher octane fuel. The octane rating of a given grade of gasoline is a measure of its detonation resistance.
If switching to a higher octane fuel fails to eliminate a persistent detonation problem, it probably means something else is amiss. Anything that increases normal combustion temperatures or pressures, leans out the air/fuel mixture, or causes the engine to run hotter than normal can cause detonation.
[B]2. Check for loss of EGR. The Exhaust Gas Recirculation (EGR) system is one of the engine's primary emission controls. Its purpose is to reduce oxides of nitrogen (NOX) pollution in the exhaust. It does this by "leaking" (recirculating) small amounts of exhaust into the intake manifold through the EGR valve. Though the gases are hot, they actually have a cooling effect on combustion temperatures by diluting the air/fuel mixture slightly. Lowering the combustion temperature reduces the formation of NOX as well as the octane requirements of the engine.
If the EGR valve is not opening, either because the valve itself is defective or because its vacuum supply is blocked (loose, plugged or misrouted vacuum hose connections, or a defective vacuum control valve or solenoid), the cooling effect is lost. The result will be higher combustion temperatures under load and an increased chance of detonation.