2008 Ford Edge misfire

[OverlandZJ]

Hi Guys.. got my sisters 08 Edge in the driveway. She dropped it off for brakes and oil change, on her way over it threw a CEL. She said the car sat for the last month..

Hook the scanner up and had 0203 and 0303 DTC's, 76K miles. Quick search on the net led me to a few threads from an Edge forum. I installed new plugs (autolite iridium) and swap the coil to cyl 6.

This is the 3.5L V6 and you need to remove the upper intake to get to rear bank (1-3cyl) so I thought I was being clever moving the coil. Installed new intake oring gasket as well. $40 from Ford.. thieves..

Anyway, get it back together and it runs smooth as silk. I change the oil, let it run while adjusting tire pressures. Get in and the CEL is back.. so I hook up expecting a 0306. Nope.. 0203 again.

I checked the wiring to injector 3 and it looked perfect, and it was connected tight.

Why would it run smooth then toss an injector code? I'm a shadetree and have been a Jeep owner the last few decades, I'd appreciate a little guidance if anyone's familiar.

Thanks..

 

[JohnX]

So the code 203 is an injector circuit fault, 303 is misfire. Both are for cylinder 3.

So did you swap coils or injectors? Not sure if that was a typo?

Next, checking the injector with a ohm meter would be a good step. If it's within spec, testing the wiring with a noid light would be in order (that will tell you if the computer is good and the wiring).

Last, you asked a question....why did it throw the code but run smooth? The computer monitors that circuit to see if the resistance is correct....it can see an inconsistency even if the injector is firing. In other words, the injector could be 10 ohm instead of 12. Far enough off for the computer to notice, but close enough for it to still work.

 

[OverlandZJ]

John, thanks for the input.. much appreciated.

I swapped the coil, not the injector. While reading the codes on scanner.. I guess I misread injector circuit for coil..

The testing of resistance and using a noid light is beyond me. I'll get a buddy here or i'll drop it off somewhere that can fix this. Trying to help my sister out..

Again, thanks for the input John.

 

[AIbandit]

This may be off topic but it appears someone has maliciously modified your name.