Were the spark plugs replaced?
Were the plug wires tested for resistance?
Since problem occurs after driving, you could have a failing ignition coil which would not work well when it is heated up after driving and cooling down makes it work better. Test the ignition coil primary and secondary resistance and also test the spraks, they should be bright blue and not dull orange.
Thursday, October 1st, 2009 AT 1:05 PM