rough idle misfire
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rough idle misfire
hello yall. i have a 2002 ford ranger xlt 3.0 i just rebuilt the entire motor about a month ago and was having a high idle problem for the longest time. turns out i had the iac on backwards. but now that it idles down around where its supposed to it has a rough idle has a little shake to it. starts up right away but when i drive down the road around 3000-3500 rpms its missing on cylinder #3 from what the code im getting "multiple cylinder misfire, #3 cylinder misfire" ive replaced plugs and wires. camshaft pos sensor. im getting 65 lbs of fuel pressure. spark on all cylinders. anyone have a clue? im really at a dead end here. also everytime i take the plugs out to look at them they look brand new. none of them are wet or have carbon on them help please
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From: Philly, PA USA
It could be the injector itself.... try switching injector with a different cyl...sometimes ohming them out doesn't show accurate because it's not on a load....it's the only other possibility besides an intake leak either from valve or gasket is unlikely due to the recent motor work done
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i did switch out an injector and the same code came back. misfire on #3. i put an old coil pack on that i know is bad bc it doesnt spark at all for cylinder #2 and it gave me misfire for #2. never gave me the code for #3. test drove it awhile with the known bad coil to see if it would throw the misfire #3 code and it didnt so that just leads me to believe that there is not and intake leak or a valve jacked up. do you think it could be a srewy coil?
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From: Philly, PA USA
how about the harness to? either the one to coil or injector... I think both parts are in series....as in all the negative wire are in series form one coil to another... positive wire goes to a pin in the PCM harness.... unplug the PCM harness and ohm that out back to cyl. #3 connectors....
even before all that make sure component side of connector has no resistance to the rear of it...not high resistance as if the connector itself were bad
It doesn't sound right that the coil is screwy to me...
even before all that make sure component side of connector has no resistance to the rear of it...not high resistance as if the connector itself were bad
It doesn't sound right that the coil is screwy to me...
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From: Philly, PA USA
i put an old coil pack on that i know is bad bc it doesnt spark at all for cylinder #2 and it gave me misfire for #2.
never gave me the code for #3. test drove it awhile with the known bad coil to see if it would throw the misfire #3 code
...... do you think it could be a srewy coil?
never gave me the code for #3. test drove it awhile with the known bad coil to see if it would throw the misfire #3 code
...... do you think it could be a srewy coil?
so the code still only gives you a misfire for #2 and no longer for #3.... so the question you would be asking is if the new coil is defective then? Sometimes I just don't comprehend things correctly, rather ask to be sure
Also is new coil Motorcraft? sometimes Ford equipment doesn't like aftermarket brands and cause electrical interferences. How about the plugs? They aren't the dumb Bosch ones either 2,3 or 4 point junk, are they? I would never use that junk for any vehicle.
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i put the old coil that i knew was bad bc it would not give spark to cyl #2 to see if it would still give me a #3 misfire. which it did not give me a #3 misfire code. so i switched them to see if it would throw another #3 misfire
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Elder User
Joined: Sep 2012
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From: Philly, PA USA
So then that would be the issue then... the coil, because no matter what cylinder you put it on, it misfires. That's logical
I misread first post, thought you had replaced coil already....long day sorry
I misread first post, thought you had replaced coil already....long day sorry
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but why is it that when i pull the plug on #3 that its not black or anything? and why would it misfire if its gettin good spark when i check the spark?
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From: Philly, PA USA
it may not be a constant misfire... it may be just enough to throw the code but not flood cylinder. I see what you are saying and know what you mean.... but it has been proven when you switched the coil to a different cylinder
the misfire also switched to that cylinder....
the misfire also switched to that cylinder....
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it may not be a constant misfire... it may be just enough to throw the code but not flood cylinder. I see what you are saying and know what you mean.... but it has been proven when you switched the coil to a different cylinder
the misfire also switched to that cylinder....
the misfire also switched to that cylinder....
Elder User
Joined: Sep 2012
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From: Philly, PA USA
It makes no sense ...It sounded so logical to me after doing that coil test you did....
I'm going to look over some notes and start from the beginning again. There are only so many possibilities. Sorry to see you have similar issues but no CEL now??. kinda makes things more difficult because at least the CEL shows what or where to start looking....
I'm going to look over some notes and start from the beginning again. There are only so many possibilities. Sorry to see you have similar issues but no CEL now??. kinda makes things more difficult because at least the CEL shows what or where to start looking....
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From: Philly, PA USA
ahhh.... how about the crank pulley/harmonic balancer? specifically the EI pulse ring.... this motor uses a crank sensor for spark timing...if the pulse ring is damaged or bent for #3 ...that's a possibility I overlooked.
Another thing to look at is the EGR system...but since you had motor apart I am not putting much emphasis there.... and also the EVAP system for blockages and such... those are all the components that would throw the CEL to begin with and now you can't even be sure which cylinder is misfiring now unless your scanner has that feature.
Another thing to look at is the EGR system...but since you had motor apart I am not putting much emphasis there.... and also the EVAP system for blockages and such... those are all the components that would throw the CEL to begin with and now you can't even be sure which cylinder is misfiring now unless your scanner has that feature.
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ahhh.... how about the crank pulley/harmonic balancer? specifically the EI pulse ring.... this motor uses a crank sensor for spark timing...if the pulse ring is damaged or bent for #3 ...that's a possibility I overlooked.
Another thing to look at is the EGR system...but since you had motor apart I am not putting much emphasis there.... and also the EVAP system for blockages and such... those are all the components that would throw the CEL to begin with and now you can't even be sure which cylinder is misfiring now unless your scanner has that feature.
Another thing to look at is the EGR system...but since you had motor apart I am not putting much emphasis there.... and also the EVAP system for blockages and such... those are all the components that would throw the CEL to begin with and now you can't even be sure which cylinder is misfiring now unless your scanner has that feature.