multi cylinder misfire?

2003 JEEP GRAND CHEROKEE
72,000 MILES • 4.0L • 6 CYL • 4WD • AUTOMATIC
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WAYNE LARSON
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  • 2 POSTS
after driving my vehicle listed above for an hour or more, will get multi cylinder misfire, (throws codes p0300, p0302, p0303, p0304, p0305) if I shut the engine off and let it coast in drive for a few seconds and turn it back on it runs fine again, it might do it again in 10 or 15 minutes, or it may not, have replaced the injectors and insulated them against heat soak, new spark plugs, all new filters, still does it.
Apr 1, 2025 at 3:21 PM
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STRAILER
  • ✓ASE Certified Mechanic
  • 54,840 POSTS
  • ASE Certified Mechanic
Does the engine make unusual noises while running? Also, does the engine have the correct weight engine oil? If not, the lifters can get over pressured and hold the valves open. Also, there is a coil pack or crankshaft angle sensor that can overheat and cause this problem as well. I would try the ignition coil pack first, here is what I am talking about for clarification. Clear the codes once completed. Check out the images (below). Let us know how it goes.


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Apr 2, 2025 at 12:00 PM
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