2000 <NOBR style="FONT-FAMILY: inherit; COLOR: darkgreen; FONT-SIZE: 100%; FONT-WEIGHT: normal" id=itxt_nobr_1_0>F-250</NOBR> 5.4L Runs great when cold. Terrible missing once warm. Have error codes that left and right banks are too rich and misses in one cylinder in each bank. Book said Upstream and downstream O2 sensors / possible EGR. There is no downstream O2 sensor and no EGR. (I have looked vigorously for the EGR)

1. - No EGR?
2. - Possible injectors that don't work well hot?
3. - Converter?

Any thoughts? Any ideas appreciated.

Thanks.
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Start with the missfire. Fix that first and see what else shows up. The coils could be breaking down. The coil resistance should be 0.3-0.8 ohms in the primary and 5.5k ohms in the secondary circuits. You can also switch the coils to different cyl. and see if the missfire moves with them.

 

I'll do that.

 

my kids expy did that and it was coils . they didn't have the cash right then too for o2 sensors and we weren't sure yet so i had her hubby take the rear ones and swap places with the front ones till they could . then , and i dont know where your egr is , i had them put some seafoam in the egr and intake let it sit to break the stuff up , and some in the tank , then fire it up . it smoked like hades for a bit but it cleared the egr code up when it was cleared out . done the same thing to my 95 bird .... it works as crazy as it seems .................