hey guys I am having some pinging issues....I am running stock timing and 92 octane gasoline...th car has not been tuned in a little while and I am smelling fuel...so I guess maybe some premature ignition is going on what should I do...I was going to take it to my mechanic but I don't wanna pay for a diagnostic and find that I only need a tune up..so should I pay for the diagnostic and then if I just need a tune that is my luck or should I just tune it and if it doesn't solve the problem pay for diagnostic?