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I have a 1989 corolla, when driving up hill I have to drop gears as the engine rattles like crazy. I changed the spark plugs which helped a bit but still rattles - is this a sign of oil leaking into the engine

Colm

From the "Ask Jack" archives - 14 December 2009

Sounds to me like the engine is 'pinking'. This can happen if the Octane rating of the fuel is too low.

If you are currently using regular 91, then make a change to Premium 95 which is the recommend fuel for this vehicle, and see if the rattle stops.

If it persists, then it's into the garage for a tune up, or a check to find the cause.