[kushane]

I purchased a 91 Civic LX about 2 weeks ago (107000 miles) and there's every indication the car was well maintained. However I have a slight pinging on the engine around 2900 - 3500 rpm under load as well as what I feel is a general lack of top end grunt after 3500 rpm. I had this same car overseas (only difference was that one was carburetted vs FI on this one) and the car overseas would really start to pull hard at the upper end of the rev range.

This one by comparison really struggles at that rpm range. I changed the spark plugs, pcv, air filter etc and even ran some seafoam thought the vaccum lines as well as add some to the tank. Filler her up with 93 octane and the ping went away. However this morning I tried 89 octane and the ping is back.

Is it possible that the timing belt on this was changed, the it was aligned one tooth off or something. Any other ideas? Thanks in advance.