Have cylinder misfire codes on two cylinders on 2000 Ford Expedition 4.6.L. Just wanted to run my thinking by the forum to see if I was correct? Either Bad coil on plug or bad plug or bad injector? I replaced the coils plugs And with generic coils and Motorcraft plugs 2 months ago, I bought on Amazon. I switched the coil on one and three cyl, and still had the same error on three after clearing the codes so pretty sure coil on plug is not bad. Thanks For any info or suggestions.

 

It could be an injector issue. If you have proper fuel, compression, timing, and spark the cylinder has to fire. If the ignition parts have been replaced and the entire cylinder bank isn’t misfiring, the issue has to be fuel or compression-related. I’d suggest swapping fuel injectors and seeing if the misfire follows the injector. If not, I’d start saving your Pennie’s for an expen$ive repair.

 

Good idea, swapping the fuel injectors, since three is one of the cylinders misfiring I can swap one and three pretty easily and then if it still misfires we know its the plug or something bigger. Thanks for the input

 

It could also be the #3 COP/fuel injector wiring/connectors are degraded causing loss of spark or fuel.
Do you have good 12v on the connector output wires of the COP and fuel injector?
Might be COP - WH/PK & FI - BN/YE if same as our 2003.
The wires go to the controller where they are grounded to complete the circuits.

 

R & T Babich, Good idea about the connectors, I didn’t even think of that, I’ll definitely put a voltmeter on them now, along with switching the one and three fuel injectors to see what effect that has. Thanks for the input