This vehicle has been neglected by previous owner.
Plugs, wires, cap, and rotor replaced. Fuel filter replaced. Ignition switch replaced (start/crank detent bad).
I traced misfire to EGR valve. Code is P300. It opens like it should after warm-up, but not before. Manually opening valve when engine is idling causes engine to stall, like it should. Initial open is too great, causing misfire at 1200-1600 rpm. Diaphragm opens wider than it should?, and then closes partially. Misfire remains, but not as severe, after initial open. If I disconnect the vacuum line to the EGR, misfire disappears. Reattaching the line causes the misfire to occur again.
Engine also has misfire at highway speeds (60 mph) in OD, but not with OD off. Check engine light is on. Light will occasionally flash when this happens. RPM at this time is 1900.
Replace the EGR? Look at the devices which control the operation of the EGR?
Plugs, wires, cap, and rotor replaced. Fuel filter replaced. Ignition switch replaced (start/crank detent bad).
I traced misfire to EGR valve. Code is P300. It opens like it should after warm-up, but not before. Manually opening valve when engine is idling causes engine to stall, like it should. Initial open is too great, causing misfire at 1200-1600 rpm. Diaphragm opens wider than it should?, and then closes partially. Misfire remains, but not as severe, after initial open. If I disconnect the vacuum line to the EGR, misfire disappears. Reattaching the line causes the misfire to occur again.
Engine also has misfire at highway speeds (60 mph) in OD, but not with OD off. Check engine light is on. Light will occasionally flash when this happens. RPM at this time is 1900.
Replace the EGR? Look at the devices which control the operation of the EGR?
Jul 11, 2008 at 12:57 PM