Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › rough idleing on ford 3.8 liter
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fordranger.
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January 8, 2012 at 11:00 am #453384
ok so i just bought a 1997 cougar (3.8 liter V6) for $500 only check engine light code that popped up was a cylinder #2 misfire. replaced wheel bearing, air n fuel filter, spark plugs n wires, and did an oil change on it. runs nice and shifts smooth but at stand still in R and D idles rough even shakes car a lil ive searched forums and it seams this motor in multiple cars have had similar issues but have a whole lot of different things to run thru just trying to put in my own forum to see what hear from of my own sources so any ideas would help greatly thank you
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January 8, 2012 at 11:00 am #453385
Step 1 for me would be to do a power balance test to see if you can nail down the effected cylinder(s). I know you say you got a code for cylinder #2 but in my experience it’s still worth going back and checking to verify that it’s actually cylinder #2 that is the problem as I’ve seen more than one occasion where that wasn’t the case and it was another cylinder that as a problem. Here’s a link to a video that I did on this.
http://www.youtube.com/watch?v=bAOmUjAjNjE
Once you find the effected cylinder(s) the next step is to find out the cause of the misfire, is it spark, fuel, or engine mechanical that’s the cause? Through a process of elimination you will find the cause and then be able to come up with a repair but first do the power balance and see what you’ve got and we’ll go from there.
January 9, 2012 at 11:00 am #453386Quoted From EricTheCarGuy:
Step 1 for me would be to do a power balance test to see if you can nail down the effected cylinder(s). I know you say you got a code for cylinder #2 but in my experience it’s still worth going back and checking to verify that it’s actually cylinder #2 that is the problem as I’ve seen more than one occasion where that wasn’t the case and it was another cylinder that as a problem. Here’s a link to a video that I did on this.
http://www.youtube.com/watch?v=bAOmUjAjNjE
Once you find the effected cylinder(s) the next step is to find out the cause of the misfire, is it spark, fuel, or engine mechanical that’s the cause? Through a process of elimination you will find the cause and then be able to come up with a repair but first do the power balance and see what you’ve got and we’ll go from there.
well when i replace the off brand wires they had which look farely new and plugs i havent had the misfire code pop back up and the motor has alot more power so i think i got past that part now its just my P0430 code popping up and it still has the rough idle tomm imma try the carb cleaner vacuum test and after that imma check for a inferred thremoter so i can check the cats so i will check back in once i get to that piont
January 9, 2012 at 11:00 am #453387Check the following:
Use of incorrect grade of fuel
Oil contamination
Fuel Pressure too high
Heated Oxygen Sensor improperly connected
Damaged exhaust system component
Faulty ECT sensor
Faulty Heated Oxygen sensor (check this last).If you check all of these and they’re good or they;re not and you fix them, then put your scanner back on and clear the codes. If the codes come back (doesn’t have to come back immediately, sometimes it will come back a day or 2 later), clear it again and disconnect the battery for 30 mins. Then reconnect it and start it up. You should be code free from then on.
January 10, 2012 at 11:00 am #453388Quoted From EndSupremacy:
Check the following:
Use of incorrect grade of fuel
Oil contamination
Fuel Pressure too high
Heated Oxygen Sensor improperly connected
Damaged exhaust system component
Faulty ECT sensor
Faulty Heated Oxygen sensor (check this last).If you check all of these and they’re good or they;re not and you fix them, then put your scanner back on and clear the codes. If the codes come back (doesn’t have to come back immediately, sometimes it will come back a day or 2 later), clear it again and disconnect the battery for 30 mins. Then reconnect it and start it up. You should be code free from then on.
how do i check for oil contamination?
January 13, 2012 at 11:00 am #453389Usually you can check with the dipstick. Usually…it’s not always the case. Also, you can drain the oil.
January 15, 2012 at 11:00 am #453393huh never knew that you’d think that engines are sensitive and that any leak at all would lean code it. i learned something new thanks i was think of an old method of a smoke test by using cigar smoke as a form of testing has anybody used it this way? and if so is it a reliable diagnostic tool?.
January 15, 2012 at 11:00 am #453390Normally it’s just a visual inspection but to be honest that’s kind of at the bottom of the list in my opinion for a rough idle misfire issue, I’d be focusing on vacuum leaks, voltage leaks, or fuel pressure issues.
January 15, 2012 at 11:00 am #453391but what if theres no lights? if theres a vacuum problem wouldn’t their be a check engine light for lean????
January 15, 2012 at 11:00 am #453392Quoted From fordranger:
but what if theres no lights? if theres a vacuum problem wouldn’t their be a check engine light for lean????
It depends on the severity of the vacuum leak.
Not all lean codes are directly related to vacuum leaks either. This is where scan tool data comes into play.
January 16, 2012 at 11:00 am #453394I’ve never tried it but it should work in principal, I’ve made videos of how I do the test along with tests for voltage leaks.
January 16, 2012 at 11:00 am #453395hey eric my question is on my coil pack (ford ranger) they have clips that need to be push together for the wire to come out and the coils casing is plastic how would i test that if its all surrounded would it make a difference?
January 16, 2012 at 11:00 am #453396If you asking how to test your ignition coil, you need to stress test it under a load with an adjustable ignition tester, obviously with ignition wires going to the coils.
January 16, 2012 at 11:00 am #453397yeah but if in theory if t was my coil pack being bad wouldn’t it have an actually misfire? that a check engine light would show up on the dash. theres no light so not bad coil and if in theory if there was a voltage leak which doesn’t make sense to me because if i was bwd wires and the coil pack doesn’t have any rust or burnt on the coil itself. im thinking my problem is more of a vacuum leak itself but a slight on. because if it was a mechanical issue itd be missing which its not and the ignition doesn’t arc or leak. does anybody know it its normal for an alternator to send a like at 5k when in passing or in neutral. my belt does have 80k and squeals when its damp out.
January 16, 2012 at 11:00 am #453398Quoted From fordranger:
yeah but if in theory if t was my coil pack being bad wouldn’t it have an actually misfire? that a check engine light would show up on the dash. theres no light so not bad coil and if in theory if there was a voltage leak which doesn’t make sense to me because if i was bwd wires and the coil pack doesn’t have any rust or burnt on the coil itself. im thinking my problem is more of a vacuum leak itself but a slight on. because if it was a mechanical issue itd be missing which its not and the ignition doesn’t arc or leak. does anybody know it its normal for an alternator to send a like at 5k when in passing or in neutral. my belt does have 80k and squeals when its damp out.
I think you should start your own post as to what problems you are having with your vehicle. See the newly stickied post by Spelunkerd as to how to post what’s going on, and you should find some good help.
January 16, 2012 at 11:00 am #453399Quoted From fordranger:
yeah but if in theory if t was my coil pack being bad wouldn’t it have an actually misfire? that a check engine light would show up on the dash. theres no light so not bad coil and if in theory if there was a voltage leak which doesn’t make sense to me because if i was bwd wires and the coil pack doesn’t have any rust or burnt on the coil itself. im thinking my problem is more of a vacuum leak itself but a slight on. because if it was a mechanical issue itd be missing which its not and the ignition doesn’t arc or leak. does anybody know it its normal for an alternator to send a like at 5k when in passing or in neutral. my belt does have 80k and squeals when its damp out.
Faulty coils will not always show as a misfire. That’s why it is best to stress test them under a load.
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