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2005 Ford Ranger - 3.0L Misfire
Posted: Mon Feb 21, 2011 11:49 am
by bloughsauto
I have a 2005 Ranger 103000 miles 3.0 cyl. 4 misfire....it only misfires at idle after engine warms up. Misfire will go away at about 1300 rpm. I have done everything I can think of. Tune up (plugs, wires, coil) swapped fuel injectors, vacuum smoke test, compression test, leak down test, cleaned MAF sensor, Changed O2 Sensors.....I scoped the injectors and plug wires and they graph the same as cyl. 6 ....has anyone had a similar issue???
Re: 2005 Ford Ranger 3.0
Posted: Mon Feb 21, 2011 12:29 pm
by Tim Martin
Without diagnosis here at my shop, I'd lean towards a sticking valve in a guide. We see this occasionally and will produce the situation you are describing. it seems like it disappears as rpms increase but is actually just not being noticed due to engine rpms.
Re: 2005 Ford Ranger 3.0
Posted: Mon Feb 21, 2011 12:36 pm
by bloughsauto
Wouldn't that show up on a compression test?
Re: 2005 Ford Ranger 3.0
Posted: Mon Feb 21, 2011 12:42 pm
by liljoe
bloughsauto wrote:Wouldn't that show up on a compression test?
Not always, the valve can be slow closing and at cranking speeds it is fast enough to be good, but at idle speed it is not closed fast enough and that cylinder misses....
Re: 2005 Ford Ranger 3.0
Posted: Mon Feb 21, 2011 12:48 pm
by Tim Martin
About the only way I know of is testing with a good ole vacuum gauge, with the emphasis on good.. At idle it will show a consistent flicker.
Re: 2005 Ford Ranger 3.0
Posted: Mon Feb 21, 2011 1:08 pm
by bloughsauto
Thanks, I am scheduling for next week to check head...,,I will post results.
Re: 2005 Ford Ranger 3.0
Posted: Mon Feb 21, 2011 1:15 pm
by Ruger77
Think of the vacuum gauge as a "running compression tester". More of a dynamic, rather than static, test.
Re: 2005 Ford Ranger 3.0
Posted: Mon Feb 21, 2011 1:24 pm
by Tim Martin
Ruger77 wrote:Think of the vacuum gauge as a "running compression tester". More of a dynamic, rather than static, test.
Excellent analogy!
Re: 2005 Ford Ranger - 3.0L Misfire
Posted: Sun Feb 27, 2011 4:59 am
by steven kiser
not at my shop computer now but if this pertains to topic it may be your issue. i've had issues with the egr port being plugged in the intake for a specific cylinder with these symptoms.
Re: 2005 Ford Ranger - 3.0L Misfire
Posted: Wed Mar 23, 2011 6:25 am
by protraxrptr17
What did you find? I have had quite a few of these have real bad valve recession. Also had one that had been to every shop in town. Heads reworked, a bunch of stuff. Anyway, it ends up here. Running rich on one bank. After much diagnostic time, I found that one shop had put in the wrong fuel injectors on that bank. Called the owner and he went to the shop and got the injectors they removed. They were also wrong. Ordered 3 new ones from ford and fixed the truck. Find out as much as you can about the history of what has been done.