ranger missing
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Junior User
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From: hickory
ranger missing
ive got a 91 ranger with a 4.0 engine/ 253000 miles on it . engine starts good and runs good while cold but when it warms up when i start to go up an incline and the autotrans.drops into overdrive and rpms decrease the engine misses, if i mash on the gas( and the trans jumps into a lower gear) the missing stops. engine also has been pinging a little but not real bad on acceleration as well . plugs only have 15k on them as well as the wires. could it be the maf ? ive heard a dirty maf will cause pinging but will it cause the missing that i have described.
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Joined: Aug 2000
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Locknut, it's possible that a dirty MAF is causing a lean condition, and therefore causing lean misfires in the cylinders. If cleaning the MAF dosen't help, I would suspect a bad plug or wire, even though they're new. They are easily checked with an ohmmeter, if you have one.
I once bought a set of plugs, that had a bad one right out of the box......
I once bought a set of plugs, that had a bad one right out of the box......
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Junior User
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From: hickory
thanks for the help. i cleaned the maf and the pinging stopped. but the missing continues, upon closer evaluation its missing on acceleration as well its just not quite as noticeable. i think ill take your advice and change the plugs next,see if that does anything.
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From: UT
Another possible cause of a misfire (and ping as well) is a leaking lower intake manifold gasket. It's quite common on the 4.0 OHV. The bolts that hold the lower intake on coem loose and allow coolant and/or oil into the cylinder which fouls the spark plug(s). The #5 cylinder seems to be where this problem rears it's head most.
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Joined: Oct 2003
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your miss under load is the spark plug wires. I have had many trucks in my shop with a miss at light acceleration, some so bad it feels like the transmission is going to jump out, repace the spark plug wires with GOOD quality wires and it will run just fine.
Last edited by shifty; Oct 19, 2003 at 10:08 AM.
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From: hickory
update--- i changed the the plugs and put in platinums. that stopped the missing i thought it was fixed then about 4 days later it started missing again the same way i described earlier. someone tell me what they think is going on.
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From: hickory
one of the plugs had some buildup on the side of the electrode, kinda ashen in color, but none were completly fouled out the way i check for that is while the truck is running pull the plug wires off one at a time when you pull one off and it doesnt effect the engine thats the bad one, none off the plugs were like that.but i really wasnt sure so i changed them all. im mad at myself for not making a note about that plug(plug #) that was the worst. i dont really want to take them all out again to check them but i may have to. i wonder, this engine has a lot of miles could low compression in one of the cylinders be causing it to miss? does low compression effect the plugs? i think ill change out the plug wires next see if that does anything.does anybody have a suggestion as to which brand to buy? i dont want the cheapest but i dont want the most expensive either.
