Engine misfire?

Tiny
STOPH8N29
  • MEMBER
  • 2006 FORD RANGER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 78,000 MILES
My truck hesitates when starting then has a lobe when idling replaced plugs wires with autolite and wires from autozone crankshaft sensor and fuel cleaner sometimes it idles rough took to dealership for diagnostic code po300, po304, po316 dealership said not o2 sensor or firing problem or fuel said could be intake gasket leak but friends and research lead to coil pack in my eyes everyone says catalytic converter could that cause a misfire and if so is anyway to test before buying couple really expensive catalytic converter or should I try gasket first or coil PLEASE HELP FORD CANT EVEN FIGURE IT OUT IN 6 HOURS
Saturday, February 14th, 2009 AT 8:30 AM

54 Replies

Tiny
BILLYMAC
  • MECHANIC
  • 2,204 POSTS
Hi yes first thing take truck to exhaust shop ask them to test convertors . this is done with a gauge and back pressure is tested high back pressure restricted .this will eliminate the expensive part.now the coil is a very good suspect. use a multi meter set the meter on ohms. ground one term remove plug wires from coil. probe each terminal on coil. are all the terminals in the same range. if yes coil is good if no coil is bad.good luck write back if you need too

This guide should help us fix it

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Please run down this guide and report back.
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Sunday, February 15th, 2009 AT 9:42 PM
Tiny
AEKNIGHT1
  • MEMBER
  • 2 POSTS
  • 2006 FORD RANGER
  • 30,000 MILES
It misfires when idling
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Wednesday, July 29th, 2020 AT 10:53 AM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,721 POSTS
Yep, an idle misfire is almost never an ignition problem, it could be a vacuum leak or a mass air flow sensor that needs to be cleaned which controls the fuel mixture. here is information on both, please heck it out and get back to me

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

and

https://www.2carpros.com/articles/mass-air-flow-service

Please get back to us so we can help you
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-1
Wednesday, July 29th, 2020 AT 10:53 AM (Merged)
Tiny
SAMELL50
  • MEMBER
  • 2 POSTS
  • 2005 FORD RANGER
  • 4.0L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 120,000 MILES
No spark on three and four when tested with HEI spark tester on coil. Have changed out coil pack, plug wires and plugs. Using procedures on easy auto diagnostics. Com there is no signal present on pin 1 per their procedure (no light flashing when engine started).

I would like to chase that red wire back to PCM, but would feel more comfortable with a diagram which shows the pin out supporting the ignition function.
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Wednesday, July 29th, 2020 AT 10:53 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning,

I attached the diagram for you of the wires from the coil to the ECM.

I would also consider the crank sensor. That is the sensor that sends a signal to the ECM for cylinder location and to ground the coil so the spark will occur.

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

and

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Have you checked for any codes in the system? Do both the key on, engine off and the engine running check.

Roy

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Wednesday, July 29th, 2020 AT 10:53 AM (Merged)
Tiny
SAMELL50
  • MEMBER
  • 2 POSTS
Thank you Roy. After looking at the diagram, I figured out I am an idiot! Having a background in electronics I seemed to ignore what a red wire typically indicates (B+). So, my test had no value. I am going to start over and pull codes for key on, engine off and the engine running check.

I noticed the wire colors on diagram do not match those on my vehicle. Starting with red, next is white/orange, then white/green, and last is white/tan.

Little background: last issue was crankshaft pulley disconnected from crank hub. Pulley went way back toward block. Visual inspection did not show any affect on Crankshaft Position Sensor. Misfire started earlier this year when I was on interstate. Started sputtering, then MIL started flashing code for Cylinder #3 misfire and multiple misfire. Slowed down and it went to normal until I pulled a hill. Replaced fuel filter. Worked great around town, then when back when pulling on interstate same condition returned. I replaced the coil pack. Worked fine for a while, then started random missing with no code. So I replaced the plugs and plug wires. Now, last check was a cylinder 3 misfire.

I will check for current codes and get back to you. It does have a bad miss which I was trying to find. However, I connected to wrong wire to coil pack.
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Wednesday, July 29th, 2020 AT 10:53 AM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Thanks.

Yes, check for any codes.

As far as the miss, do a compression test to be sure there is no internal engine issues.

https://www.2carpros.com/articles/how-to-test-engine-compression

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Roy
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Wednesday, July 29th, 2020 AT 10:53 AM (Merged)
Tiny
MOTLHABANE
  • MEMBER
  • 6 POSTS
  • 2004 FORD RANGER
  • 4.0L
  • V6
  • 2WD
  • MANUAL
  • 266,224 MILES
Spark intervals are not consistent and therefore causes the car to misfire as if not on timing or wrong firing order. We can't even find obd plug.
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Wednesday, July 29th, 2020 AT 10:57 AM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
Data link is below dash on left hand side, get codes and re post for further assistance.
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Wednesday, July 29th, 2020 AT 10:57 AM (Merged)
Tiny
MOTLHABANE
  • MEMBER
  • 6 POSTS
Good evening! Thanks for response to my previous request. We found the Data link and therefore tried to do diagnostics. Unfortunately the system we used couldn't give us option for this Ford Ranger model. And the system we've been using is " Auto Boss V30 SPX. Please advise me further in this regard.
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Wednesday, July 29th, 2020 AT 10:57 AM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
You will have to find a quality scanner as I will require the set codes to work out the problem you are having
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Wednesday, July 29th, 2020 AT 10:57 AM (Merged)
Tiny
MOTLHABANE
  • MEMBER
  • 6 POSTS
Good day Sir, the only data that reflects repeatedly is P1000
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Wednesday, July 29th, 2020 AT 10:57 AM (Merged)
Tiny
RMT2323
  • MEMBER
  • 3 POSTS
  • 2004 FORD RANGER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 60,000 MILES
In neutral or park, engine starts missing @ 3000 rpm. Will not run above that rpm. Take truck on road and it performs perfect; no miss, no hesitation, accelerates right through to 5500 rpm.
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Wednesday, July 29th, 2020 AT 10:57 AM (Merged)
Tiny
IMPALASS
  • MECHANIC
  • 3,112 POSTS
Hello -

To better assist you can you tell me your engine size in liter and the 8th digit of your VIN.

Also, please go to Auto Zone (AZ) or O'Reilly's (OR) and for FREE they can pull the codes to the car. Most important: Once they check your codes, if they find something and you don't get it fixed and need to get back with us, please make sure you tell us exactly what the code was, number and all. Example, if the code was E0568 O2 Sensor bad. Then make sure you give us all of that. While there for FREE also they can bring their tester out and check your battery and alternator.
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Wednesday, July 29th, 2020 AT 10:57 AM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
This code is set after an ECU re flash, you may just need to do a drive cycle to do the re learn first.
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Wednesday, July 29th, 2020 AT 10:57 AM (Merged)
Tiny
RMT2323
  • MEMBER
  • 3 POSTS
It is a 3.0 litre and the 8th digit of the vin is the letter U. Also, is it possible there is a rev limiter for when the truck is not in gear?
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Wednesday, July 29th, 2020 AT 10:57 AM (Merged)
Tiny
MOTLHABANE
  • MEMBER
  • 6 POSTS
Good day! Thanks for previous response. I'm not very sure if by drive cycle you mean I should drive around, but the car doesn't start. It sound like releasing a low spark.
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Wednesday, July 29th, 2020 AT 10:57 AM (Merged)
Tiny
IMPALASS
  • MECHANIC
  • 3,112 POSTS
Hello -

Thanks for getting back with me.

Did you have time today to perform the checks for codes, battery etc?
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Wednesday, July 29th, 2020 AT 10:57 AM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
In your original question you said it was misfiring, now you say I does not start, what is it doing exactly, I need correct info to try and help.
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Wednesday, July 29th, 2020 AT 10:57 AM (Merged)
Tiny
RMT2323
  • MEMBER
  • 3 POSTS
I did have the battery and altenator checked and they were both functioning prorerly. The check engine light did not come on and there were no codes.
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Wednesday, July 29th, 2020 AT 10:57 AM (Merged)

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