65k on car ..have changed computers and tps.with original computer car had flat spot in acceleration between 30-40 mph ..accelerating forcefully results in car going beyond this speed and then smoothing out just fine.replacement used computer caused the same type of problem except that it happens between 60 and 70 mph..checked grounds and vacuam hoses..one mechanic has said the computers for these cars are matched to the speedometer clusters??any advice appreciated.