Had problems with misfiring. Dealer replaced two bad plug wires and ox sensor. Problem seemed to be fixed. Or was it? If the vehicle sits for over a day it misfires and the service engine light comes on. By the second day of operation the misfiring stops and the engine service light goes out. Misfire only happens below 2,000 RPM which when in D is most of the normal operating range. At higher RPMs I can make it go away. Any thoughts before I take it back to the dealer?

 

Back to the basics, what year is your truck and what mileage??
You need to have someone scan the engine for a code while the check engine light is on.
I believe the dealer only went part way with their repair.
Get back to me.
Mike