On higher mileage vehicles, one or more EGR orifice in the intake manifold may plug with sludge. This can cause the engine to misfire when first accelerating because too much exhaust gas is directed into the cylinders where the orifice is not plugged. Cleaning the clogged passages should correct this concern.
Average mileage: 88,875 (55,000–145,250)
Exhaust & Emissions affected: 4.2L V6
13 people reported this problem
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On acceleration even at higher speeds my truck truck balks and hesitates.
ENGINE MISFIRES WHEN COLD AND STARTING OFF AT LOW SPEED
After changong all 8 coils motor still hasitaitig at slow speeds.
Mechanic has said that he has never seen anything like what happened to my truck. I got a new radiator cause I was leaking antifreeze. It still kept leaking. Now the mechanic is saying it is my intake manifold and that there is some gunk inside it that he has never seen this happen. The fixing will be about six hundred plus dollars. I am trying to see if there was a recall or something that can help me with this problem.
slow to start and once started idles very ruff and with poor performance