it does seem obvious that is something with #1. I have done all those swaps. It was always cylinder 1 and still it’s cylinder 1 after replacing all plugs, wires, coil packs and replacing the injectors with rebuilt ones from a different vehicle. How likely is it that one of those new components is faulty, and I just happened to install it on cylinder 1 again? I tested continuity and function of the wiring harness injector lead. That is the only part you mentioned that I have not replaced. Do you suggest that somehow Good when tested but intermittent while operating? Could it be the ECM somehow?

 

Recently went through tis with another poster, he got injectors off ebay that were bad out of the box. Swapping components between cylinders is not the same as putting in new components. There can be bad components that are new.

 

So, the way l'm reading this...you clear codes and immediately get pending codes before you even drive or start it? Do you notice any signs of water damage in ECU area, under glovebox? Wet carpet or corrosion in that area?

 

if I reset codes it takes a little while for the pending codes to come on. Usually I drive it a mile or so before I see them. I should try just letting it idle to see if they ever come if I don’t drive it. It normally takes 3 or 4 Driving cycles to trigger the SES. I don’t see water damage but don’t know what this vehicle has been through in the past. It had codes when I bought it. I have another vehicle I cold swap ECMs with but I understand that It won’t start unless it take all the computers. Right? If it seems like it could be ECM, I could try that as a diagnostic.

 

Check the 15A fuse F2 in the engine bay to see if it's blown.

 

have you tried taking it out on the highway and driving it hard and at higher RPMs for a bit?

 

Fuse F2 is intact.

 

Yes. I have. It feels pretty normal. Is there something I should be looking for?

 

i have a 2000 Discovery that is throwing occasional misfires.

we can drive it around town with no issues for several days then get some misfires. if we take it out on the highway at higher speeds alternated with higher RPMs the misfires go away for several days again. sometimes weeks. not sure if it is valve train related or injectors. but was curious to compare data.

 

Are you saying it feels like the misfires go away, or the misfire code goes away?