Hesitation on 2004 Mercury Sable

This car has 82,000 miles, been babied, and kept up on repairs as needed. When speed gets up to about 25-30, car hesitates. Took it to Advance Auto, they tested it, found cylinder misfire problems (times 3). Replaced plug wires, and plugs- still the same. Please help. This is my sons car- and he is frustrated.

1 answer
A low Compression on a Cylinder would indicate a misfire as well. Suggest have a qualified mechanic perform an Engine Compression test of your Engine. Failure of Electrical components such as a Camshaft and Crankshaft sensors would also indicate a misfire. Fuel Injector problem will also cause a misfire problem. Best to have a qualified mechanic perform a full Diagnostic of Fuel system. Ignition system. Computer control system and Compression test.