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Engine starts to misfire?

Tiny
PUERTORICO1963
  • MEMBER
  • 2 POSTS
  • 1999 FORD RANGER
The check engine light came on so I put my scanner on it and it said that cylinder 2 and 6 was misfire so I replaced those 2 spark plugs and it still read the same so I changed all the plug wires and it is still reading that cylinder 2 and 6 has the misfire and the truck still has a miss so what could be the problem?
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Wednesday, July 29th, 2020 AT 11:11 AM (Merged)
Tiny
D0SITMATR
  • MEMBER
  • 8 POSTS
Ok, so I feel like a complete buffoon.

Out of 4 plugs I tried, including a brand new one, only 1 of them came out to be any good.
The new one had a weak post, another had a hairline crack that was unnoticeable until you almost looked at it through a magnifying glass, the last failed one was the one in the pic supplied above.
The only reason I even bothered looking was due to checking to make sure the new one was seated correctly this morning, and that is how I found the post was weak. But my coil is still throwing a weak spark to one of the plugs anyways, so my guess is it was a combination of the two, 1 or the other by itself would allow the truck to run almost normal, but both together was killing it.
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Wednesday, July 29th, 2020 AT 11:11 AM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Have you checked the compression on those cylinders?You made sure you had a nice blue spark on those two cylinders?
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Wednesday, July 29th, 2020 AT 11:11 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,740 POSTS
Sorry about the delay in responding to you. I lost a family member and things have been.

Regardless, I'm glad it's fixed. As far as identifying that type of problem, anyone would have missed it. When you get new plugs, you don't expect them to be bad.

Take care and let us know if you have questions in the future.

Joe
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Wednesday, July 29th, 2020 AT 11:11 AM (Merged)
Tiny
PUERTORICO1963
  • MEMBER
  • 2 POSTS
Yes I have did this and the compression is good on both of them. It only missing while its idle but when I run it on the road it runs fine but when I stop at a red light it misses again
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Wednesday, July 29th, 2020 AT 11:11 AM (Merged)
Tiny
D0SITMATR
  • MEMBER
  • 8 POSTS
Joe, thank you for the help
I am truly sorry to hear of the loss, I hope your doing well.

Sincerely
Michael
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Wednesday, July 29th, 2020 AT 11:11 AM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
We need to look for a vacuum leak
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Wednesday, July 29th, 2020 AT 11:11 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,740 POSTS
Thanks, Michael. After the loss of my mother a little over a year ago, my father went down hill. He was 85 and remained a stone mason nearly till the end. He was always so strong and healthy. I just can't believe he is gone. I guess time will help.

Thanks again, and let us know if you have questions in the future.

Joe
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Wednesday, July 29th, 2020 AT 11:11 AM (Merged)
Tiny
BARBARA1963
  • MEMBER
  • 99 POSTS
  • 1999 FORD RANGER
Wow I dont even know where to start on this one-i have already talked to you about the problem i've had with this truck and all the things i've changed but now the check engine has come back on and its telling me cylinder 2 and 6 are misfiring again so do you think it is the injectors because I have changed the plugs and plug wires, coil, and checked the compression which is good and it ran fine for 1 week but now its showing 2 and 6 again
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Wednesday, July 29th, 2020 AT 11:12 AM (Merged)
Tiny
CARADIODOC
  • MECHANIC
  • 33,871 POSTS
You didn't say which engine you have but I can offer a few suggestions. Since you did the ignition coils or coil pack already and you suspect the injectors, try switching those from cylinders 2 and 6 with two from different cylinders, erase the fault codes, then see if codes set for those other cylinders instead that you moved the suspect injectors to.

If your engine uses an EGR valve, disable it or block the port to see if that solves the misfire. Some engines use a passage to each cylinder and those can become blocked. Those cylinders don't get any exhaust gas so they run fine. It's the cylinder(s) that aren't blocked that get the full volume of that inert gas. That displaces so much fresh air and fuel that they misfire.
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Wednesday, July 29th, 2020 AT 11:12 AM (Merged)
Tiny
CHANCEBASE
  • MEMBER
  • 3 POSTS
  • 1998 FORD RANGER
  • 4 CYL
  • 2WD
  • MANUAL
  • 60,000 MILES
Was running fine when I parked in garage. When I started two days later engine idled exteremly rough, extreme shaking, engine near stalling. When accelerator is depressed halfway down engine begins to stall then speeds up then stalls then speeds up. This cycling continues as long as accelerator in depressed. I changed gas filter. I also checked fuel pressure at injector rail and found pressure within specs when engine not running key on. When engine barely running at idle fuel pressure increased but still within specs. What do I need to check next?
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Wednesday, July 29th, 2020 AT 11:12 AM (Merged)
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Have you checked the air filter to see if anything is in it like a mouse nest or anything? If this checks out ok then if you would unplug the Mass Aif Flow meter and start it and see if idles ok then. Get back to me with what you find.
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Wednesday, July 29th, 2020 AT 11:12 AM (Merged)
Tiny
CHANCEBASE
  • MEMBER
  • 3 POSTS
Had already checked filter etc.
Uplugged mass air flow meter as you instructed.
Started Engine and idled and ran engine. Runs normally at idle and when accelerated. I take it the mass air flow meter needs replaced.
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Wednesday, July 29th, 2020 AT 11:12 AM (Merged)
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Ok if unpluging the mass air flow sensor makes it run normal or better then yes it needs replaced or maybe just cleaned. You can try cleaning it with mass air flow cleaner first. Let me know how it goes.
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Wednesday, July 29th, 2020 AT 11:12 AM (Merged)
Tiny
CHANCEBASE
  • MEMBER
  • 3 POSTS
I cleaned mass air flow sensor with approved cleaner. "Didn't do the trick." Replaced sensor, problem solved, engine running great. I want to thank you for sharing your time and knowledge it is greatly appreciated!
Thank you!
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+1
Wednesday, July 29th, 2020 AT 11:12 AM (Merged)
Tiny
JIMG2
  • MEMBER
  • 2 POSTS
  • 1998 FORD RANGER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 82,500 MILES
My records show the fuel filter was replaced at 55000 miles when a tuneup was done. When your between misses the engine feels fine. Should the Fuel filter be changed again.
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Wednesday, July 29th, 2020 AT 11:12 AM (Merged)
Tiny
BMRFIXIT
  • MECHANIC
  • 19,053 POSTS
Are you getting check engine light on
if so you should get it scanned for codes
also fuel filter should be replaced as well checking tune up.
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Wednesday, July 29th, 2020 AT 11:12 AM (Merged)
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Great glad to hear it is running as it should again. If there is anything else you need just ask.
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Wednesday, July 29th, 2020 AT 11:12 AM (Merged)
Tiny
JIMG2
  • MEMBER
  • 2 POSTS
There is no "CHECK ENGINE" warning light. You feel the miss then your fine for 30 seconds then it nisses again.
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Wednesday, July 29th, 2020 AT 11:12 AM (Merged)
Tiny
BMRFIXIT
  • MECHANIC
  • 19,053 POSTS
Check the tune up

also have cylinder balance test done
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Wednesday, July 29th, 2020 AT 11:12 AM (Merged)

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