The EGR orifices in the intake manifold may plug with sludge. If the truck has high mileage, this may cause engine misfire when first accelerating because too much EGR gas is directed into the cylinders of the unplugged orifices. This makes the mixture lean, which causes a gradual stumble that increases in severity until repaired.
EGR orfice in intake may plug with carbon on Ford F-150
Average mileage: 113,699 (25,798–215,000)
Exhaust & Emissions affected: V6
7 people reported this problem
1998 Ford F-150 215,000 mi, Visitor
Engine develops intermittent miss. Pull intake plenum and clear egr ports in intake manifold.
1997 Ford F-150 25,798 mi, Visitor
run lean bank 2