my car is pinging under when i accelerate. it gets worse the harder i accelerate and doesnt start until after 3000rpm in forth gear. it cant be the octane grade because itll do it with 91 octane(highest in CA). any ideas on what could be the cause?
First do a search on pinging there are tons of threads on it.
Second Change your timing back to 10.
Third Clean your MAF real good.
Forth check your fuel pressure.
YOu might also be running out of fuel. 4th gear, high RPM and accelerating creates the largest burden on the fuel system. If you can have a friend watch FP while this occurs, that could be helpful......
my car is pinging under when i accelerate. it gets worse the harder i accelerate and doesnt start until after 3000rpm in forth gear. it cant be the octane grade because itll do it with 91 octane(highest in CA). any ideas on what could be the cause?
What mods do you have? If you have several, maybe the fuel pump's maxed out at higher revs and unable to keep up with the demand, causing the engine to run lean. The stock fuel pump only puts out a maximum of 88lph or 145lb/hr (that's ~18lb/hr for each injector). If you assume a BSFC of ~0.5, that means it'll only feed ~290 or so crank HP.
The timing could be the problem so return it back to 10*BTDC as the first measure.