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Solved 01 Explorer - CONFUSED...Cylinder 1 Misfire and Lean on Bank 1

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Panteruh

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December 28, 2009
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City, State
Omaha, Nebraska
Year, Model & Trim Level
2001 Ford Explorer XLS
Good afternoon,

Hoping someone might be able to offer some tips. Here is the situation.

2001 Ford Explorer XLS.

Had all plugs and wires changed about 2 months ago. Vehicle was running decent and then two days ago, while I was driving, I noticed a slight roughness in performance and check engine light came on.

Now the car idles at about 500 when at a stop.. it is very churny and chuggy until about 1000 RPMS... Engine seems like it has a significant loss of power. It is technically "drive-able" it hasn't died yet... but it isn't exactly a pleasant experience knowing it isn't running properly.

Every now and again the CEL will flash at me for a moment but then go back to solid. This doesn't happen often.. maybe 3 times in the last week. I know flashing is bad.

Codes came back with Cylinder 1 misfire and Lean on bank 1.

- Checked the wire and plug, didn't notice anything. Still replaced them just to be safe with new. No difference in performance and still getting same codes.

- Replaced Ignition Coil with new - no difference.

- Did a water test at night, couldn't see any visible arcing or sparking - so ignition/spark doesn't seem to be the problem.

My next plan is to check out the fuel injector for that plug and see if there is issue there as well as the PCV hoses and ensure there is no leaking (there does not appear to be any leaks from what I have seen) after that check out the intake manifold and see if there is a leak there in the gaskets.

This vehicle has 214,000 miles on it and I'm guessing most of these things (even up to the sparks that were changed 2 months ago) are stock.

Am I barking up the right tree here or is there something else I could be missing. Asking for anyone with some experience to throw me some input.

Thanks!!
 



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01 Explorer - Misfire on 1 and Lean on Bank 1

Good afternoon,

Hoping someone might be able to offer some tips. Here is the situation.

2001 Ford Explorer XLS.

Had all plugs and wires changed about 2 months ago. Vehicle was running decent and then two days ago, while I was driving, I noticed a slight roughness in performance and check engine light came on.

Now the car idles at about 500 when at a stop.. it is very churny and chuggy until about 1000 RPMS... Engine seems like it has a significant loss of power. It is technically "drive-able" it hasn't died yet... but it isn't exactly a pleasant experience knowing it isn't running properly.

Every now and again the CEL will flash at me for a moment but then go back to solid. This doesn't happen often.. maybe 3 times in the last week. I know flashing is bad.

Codes came back with Cylinder 1 misfire and Lean on bank 1.

- Checked the wire and plug, didn't notice anything. Still replaced them just to be safe with new. No difference in performance and still getting same codes.

- Replaced Ignition Coil with new - no difference.

- Did a water test at night, couldn't see any visible arcing or sparking - so ignition/spark doesn't seem to be the problem.

My next plan is to check out the fuel injector for that plug and see if there is issue there as well as the PCV hoses and ensure there is no leaking (there does not appear to be any leaks from what I have seen) after that check out the intake manifold and see if there is a leak there in the gaskets.

This vehicle has 214,000 miles on it and I'm guessing most of these things (even up to the sparks that were changed 2 months ago) are stock.

Am I barking up the right tree here or is there something else I could be missing. Asking for anyone with some experience to throw me some input.

Thanks!!
 






i'd be checking the fuel injector. injector #1 may not be working.
 






Thanks, that's what I'm thinking is the issue... unfortunately I don't know anything about fuel injectors, as in, if they normally just all of a sudden go bad on you while you are cruising down the road. :)
 






Thanks, that's what I'm thinking is the issue... unfortunately I don't know anything about fuel injectors, as in, if they normally just all of a sudden go bad on you while you are cruising down the road. :)

an injector is an electrical solenoid valve, so yes they can just go bad driving down the road. it could also be a wiring problem, or even a PCM problem. i'd start with the injector. you can even try switching #1 with another injector and see if the problem follows.
 






Thanks man, I'll start there and see what happens and report back. Probably won't dive in until the weekend... its my only vehicle and I've never screwed with those components before so I want plenty of time.
 






Sounds like an air leak to me. Could be intake manifold, injector seal, etc. It could also be the injector, as mentioned. That's worth checking too.
 






I might get real suspicious of the #1 fuel injector. If it's failing to get enough fuel into the cylinder for ignition, you'd get the miss fire fault and excess air getting into the rest of the exhaust system causing the "lean bank 1" condition.

As the ECU tries to compensate on bank 1, it'll richen the other cylinders that will ultimately cause so much fuel into the system that ignition fails there too causing the flashing check engine light from unburt fuel getting to the O2 sensor.
 






Thanks for the input, I really appreciate it.

I'm really leaning towards the injector as well. Probably have to wait until this weekend since I've never tackled that sort of thing before and want some time to mess around. I might go to the junkyard on Friday and find an explorer to practice on. :)

I have an ohm meter in the mail as well as a auto stethoscope.. so hopefully that will really help diagnosing the injector.
 






Might be worth a try to put a noid light on that injector 1st -- many auto parts houses have loaner tools that include noid light sets.

The noid light will let you know if the PCM is trying to trigger the injector or not.

Practicing at a u-pull-it is a great idea, probably a good idea to buy at least 1 injector from your practice session but I would suggest a fresh set of injector o-rings.
 






Just wanted to update - Turned out to be bad number 1 fuel injector. Put an auto stethoscope to it... didn't sound the same as the others... when I got to the point I was able to put a multimeter on it - it wasn't reading at all.

Replaced - all good.

Thanks for the tips guys.
 






Just wanted to update - Turned out to be bad number 1 fuel injector. Put an auto stethoscope to it... didn't sound the same as the others... when I got to the point I was able to put a multimeter on it - it wasn't reading at all.

Replaced - all good.

Thanks for the tips guys.
 












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