put in a can of 104 octance...you have a leaning out problem in that range a chip will fix this ...you lucky so far you have't lost a head gasket...pull timing back 2 degrees

 

I have a pinging noise in my cobra also, I use 93 octane everytime. I have new fuel pump, injectors, spark plugs, cmputer chip, procharger and som much more. The noise really makes me nervous. Im not running the car at all untill I have time to look at the problem. Way to much money in the engine for something to go wrong.

 

Let me rephrase from my earlier post saying mine was pinging at around 4k.. It's not actually a valve pinging I'm hearing. It sounds more like intake gases popping thru the intake which could be possibly construde pinging.. I've only noticed this at speeds above 100mph. With all that said. Mine is not pinging (valves). Your milage may vary. -=cobrakid=-