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fastback 427

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Re: 390 missing
« Reply #15 on: July 25, 2015, 02:01:31 PM »
What plugs and wires are you using? Are the plugs and wires resistoror non resistor?  Mismatching those can cause a miss and erratic combustion.
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Jaime
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Joe-JDC

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Re: 390 missing
« Reply #16 on: July 25, 2015, 08:20:10 PM »
Forgot one of the basic things to check for skip with FE, and that is the 7-8 plug wires arcing under certain conditions.  Try to make sure those plug wires are completely separated, even though you may have a new set.  Also, if the distributor cap has carbon tracking inside, you will have issues with skipping.  Joe-JDC
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Joe-JDC '70GT-500

390owner

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Re: 390 missing
« Reply #17 on: July 28, 2015, 05:58:58 PM »
I just cant figure this thing out. The last two times I have driven the bronco the 390 as not missed a lick when cold. I tried hard to make it this morning by lugging it in 4th but it just ran like a top. I give up.
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shady

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Re: 390 missing
« Reply #18 on: July 28, 2015, 06:09:35 PM »
bad gas? or water in it?
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390owner

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Re: 390 missing
« Reply #19 on: August 23, 2015, 07:19:44 PM »
Ok now the 390 is doing something a little different. It would only miss when cold. Today we went to visit our son at collage. It was a little over an hour drive. It would miss or surge every time the rpms got below 2000 like when I took a sharp curve then gave it gas to speed back up. It felt to me like it was starving for gas but if I mashed the gas down it smoothed out. I dont know what to do now but I need it fixed because it is getting worse.
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390owner

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Re: 390 missing
« Reply #20 on: August 25, 2015, 08:20:50 PM »
I guess everyone is out of ideas??
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Dot Heton

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Re: 390 missing
« Reply #21 on: August 25, 2015, 09:29:38 PM »
Don't forget to check your distributor for play and your timing chain also.
 My 390 has the same miss when cold.
I have to ask about the sticky valve, is this because of a worn guide or gunk buildup?
With the lifter not pumping up, is this an oil flow issue or the lifter itself?
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Joe-JDC

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Re: 390 missing
« Reply #22 on: August 25, 2015, 10:29:32 PM »
It still sounds like water in the fuel.  When the rpms are higher, the miss is undetectable, but when slowing down, it will be noticeable.  Turns, or curves will accentuate the issue with water moving around in the tank and getting sucked up.  I would add at least two bottles of water dispersant/fuel injector cleaner type additive to the tank when it is low of fuel, and then fill up at a reputable station that is not refueling the tanks while there.   I would even add a can of cleaner with each tank for a couple of tanks to make sure any and all condensation is removed from the bottom of the tank.  I always fill the tank full when refueling to lessen the chance of moisture/condensation forming between fill-ups.   Joe-JDC
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Joe-JDC '70GT-500
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