High Octane fixed My Engine Knock :-)

[solaris=amazing]

A while back i posted about my engine pinging/knocking when floored-someone suggested to me to jump straight to 93 high octane, instead of the normal 87 regular. So when the tank was like 90% empty, i filled her up on the 93, then maybe two days later, after driving alot i filled her up again on the 93. This has fixed my problem bigtime, it's still there but about 80% gone. Another thing is, i found out i do in fact have spark plug knock-gonna get it tuned up in a week. Open the hood and from the back you get a constant tick tick tick tick. It does speed up on heavy acceleration also.

ps.. Also put in chevron with techron, on all my cars in the past this always helped. But it was mainly the 93 gas that cured it.

[Bray Hill]

I believe the problem is your egr valve. EGR is added to the intake charge to reduce NOx emmisions. In late model t-birds they use the EGR to improve fuel economy by adding a lot of spark advance when the EGR is enabled. A rough rule of thumb is that for evey single percent increase in EGR, the ignition is advanced 2 degrees to offset the slower burn due to the dilution effect of EGR on the intake charge. Therefor if your engine is running 10% EGR the timing is advanced by 20 degrees, and if the EGR is not present the 20 degrees ignition timing advance over non-EGR mode will most likely result in predetonation. This could be caused by a failed EGR valve, restricted EGR feed port, loss of vacuum signal, or so on. EGR is only fed into the intake at high rpm or throttle levels wich explanes your full throttle predetonation problems. Also high octane fuel burns slower and works better at higher spark advance levels and would help to reduce predetonation or spark knock, whatever you want to call it.

Drive it like you stole it.