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Old 05-08-2013, 10:00 AM
cowboybilly9mile cowboybilly9mile is offline
Ford Ranger Driver
Join Date: Mar 2010
Posts: 4,900
Default Re: Engine miss.............

Originally Posted by JMJ View Post
...........The code for the engine check at Auto Zone was #3807, OEM number to cross was P0300. .................JMJ
Random misfire, generally caused by lean mixture. So make sure the egr valve is seating correctly and verify that there is no vacuum leak of any kind. Clogging fuel filters initially result in fuel starvation at high engine RPM's, like on freeway on ramps and you're not talking about that, so you don't have a filter issue. Seadouch could be used as a substitute for ford PM-3 on early 4.0's to implement the decarbon TBS, but since you don't have a 4.0 and thus don't have that issue, there is no value in running seadouch in your engine other than to help the manufacturer profit and to wash crap onto your new plugs, with the typical result being carbon fouling and the need for new plugs. Since the DTC was random misfire, that would tend to rule out a single bad injector due to the random thing. IMO, for now, focus on logical things that would cause a lean mix, like vac leak issues and the EGR. You could do a compression test for piece of mind, but I'd expect that it will result in rulling out any mechanical problems. Bonus points if you can find a Ford Factory Service manual and follow the diagnostic procedures for P0300.
2004 Ranger FX4 Level II, 5R55E, Sonic Blue Pearl

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