P0304
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P0304
Hi, I am new here . This seems like a great site with lots of great information. I have a 2002 Ford Expedition that I am having trouble with. Last week the MIL lamp came on with a code of P0304(miss on cylinder #4). The truck has 76000 miles so I figure it is time to change the spark plugs ( that was fun) and also change fuel filter. I clear the code and every thing seems fine for a day or two. The MIL lamp comes on again with a code of P0304, so I swap the #4 COP with the #1 COP and clear code. The MIL lamp comes on again with a code of P0304 so I now swap the #4 injector with the #1 injector and clear the code. The MIL lamp comes on again with a code of P0304. Next I check the #4 injector wiring with a NOID light. Next I disconnect the battery overnight so the computer can do a relearn ???( suggested by a coworker). Now the truck still has a miss and seems to be lacking power, but with no MIL and no pending codes. Where do I go from here? THANKS
Last edited by BeauHymel; Jan 30, 2008 at 04:51 PM.
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Well, you have moved everything you can. The Noid isn't going to catch a intermittent wiring. How are you telling that it is missing now, fell or is the MIL flashing?
One thing you didn't check is compression or a massive vacuum leak on #4. I'd say it is in the wiring. I'd begin tracing backward looking for a marginal or corroded connector.
One thing you didn't check is compression or a massive vacuum leak on #4. I'd say it is in the wiring. I'd begin tracing backward looking for a marginal or corroded connector.
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Thanks for the quick reply. You can feel the miss mostly while driving, 45 to 50 MPH after the torque converter locks up. The next day off I hope to check compression and vacuum. Do you know about what vacuum sould be at idle? Thanks again
Laughing Gas
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Originally Posted by BeauHymel
Thanks for the quick reply. You can feel the miss mostly while driving, 45 to 50 MPH after the torque converter locks up. The next day off I hope to check compression and vacuum. Do you know about what vacuum sould be at idle? Thanks again
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OK I checked my vacuum and it is a steady 21" at idle. The m missfire is getting better??? It is bearly noticable from idle to ~3000RMP and is gone above 4000RPM. I am really stumped. Any other ideas as to what to look at? Thanks again.
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