Rough idle/Ignition issues?
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Cross-Country
Joined: Feb 2013
Posts: 85
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From: Gibsonville,NC
Rough idle/Ignition issues?
Hello all, I’m having an issue with my 86’ F-150 5.0 EFI with AOD transmission. It has started to shudder bad recently, so much so that it shakes the change in my ashtray out. This happens when cranked, when up to temp and throughout acceleration. My first thought was it’s time for a new distributor cap and rotor, which I replaced yesterday. It has helped somewhat but it’s still there. I did a tune up kit about 1.5 years ago with heavy gauge wires, plugs,cap and rotor. Where should I look next? Anyone have any recommendations or had the same issue before? Thanks for your help.
Lead Driver
Joined: Nov 2013
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Anything else we can help solve?
Does your truck have the TFI or Duraspark ignition? I think EFI had the TFI system, but am not positive.
If Duraspark, check if the spinning bits are hitting the stationary bits inside the distributor:
https://www.ford-trucks.com/forums/1...tator-gap.html
On a Duraspark distributor, also check if the wires from the pickup coil are rubbing against the housing and shorting out. These wires flex as the vacuum advance mechanism moves, causing an intermittent problem.
Moderator
Joined: Jan 2001
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From: Virginia
If it's shaking with a steady rhythm, you may have a dead cylinder. To test this you can take one at a time all the wires off the sparkplugs and then put them back on to loosen them up. If you think it would be easier to do it on top of the distributor cap you can loosen those. Then get the engine running, and while it's running bad, put on a glove, you can use pliers too, and pull the sparkplug wires off one at a time.
If you pull a wire and it makes the engine run worse, then that cylinder is working. If you pull the wire off and it makes no difference, then that cylinder is dead. Go around and try all of them.
If you pull a wire and it makes the engine run worse, then that cylinder is working. If you pull the wire off and it makes no difference, then that cylinder is dead. Go around and try all of them.
Lead Driver
Joined: Apr 2002
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If it's shaking with a steady rhythm, you may have a dead cylinder. To test this you can take one at a time all the wires off the sparkplugs and then put them back on to loosen them up. If you think it would be easier to do it on top of the distributor cap you can loosen those. Then get the engine running, and while it's running bad, put on a glove, you can use pliers too, and pull the sparkplug wires off one at a time.
If you pull a wire and it makes the engine run worse, then that cylinder is working. If you pull the wire off and it makes no difference, then that cylinder is dead. Go around and try all of them.
If you pull a wire and it makes the engine run worse, then that cylinder is working. If you pull the wire off and it makes no difference, then that cylinder is dead. Go around and try all of them.
Lead Driver
Joined: Jun 2013
Posts: 5,651
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From: Tolland, CT
Another way to check, is with engine running, pull the spark plug wires one at a time and see if the engine changes ? replace that wire before pulling the next one. They make plastic pliers to help do that, hint, you might want to make sure each plug wire moves freely first.
FTE Legend
Joined: Nov 2015
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From: Angier, NC
And since you are there when the plugs are out do a compression test and write down the readings and report back.
Another way to check, is with engine running, pull the spark plug wires one at a time and see if the engine changes ? replace that wire before pulling the next one. They make plastic pliers to help do that, hint, you might want to make sure each plug wire moves freely first.
Dave ----
Lead Driver
Joined: Jun 2013
Posts: 5,651
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From: Tolland, CT
And gee, I just got back from my eye doctor's... I guess that didn't help LOL
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Lead Driver
Joined: Apr 2002
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I was going to suggest the compression testing too, but I had to leave right away so left that off. Be sure you have a well charged battery for that.
I guess the OP said 1.5 years on the plugs. I missed that, but if he's an average daily driver that could be 30k miles. Due for new plugs indeed.
I guess the OP said 1.5 years on the plugs. I missed that, but if he's an average daily driver that could be 30k miles. Due for new plugs indeed.
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FTE Legend
Joined: Nov 2015
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From: Angier, NC
I forgive you this time as it can be hard to see the screen after the eye doctor
Dave ----
Lead Driver
Joined: Jun 2013
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From: Tolland, CT
I hope the OP updates us soon... ???? Gee, the GF and I went on a 3 day get away (2.5 hour drive) to Cape Cod and did a whale watch and have some good seafood. Oh yeah, buy T-shirts and the like...LOL
FTE Legend
Joined: Nov 2015
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From: Angier, NC
Did you get to see any whales? T-shirts are always a good thing.
Last fall wife & I and 2 other couples went to the NC outer banks, wife wanted to see the wild horses but is was after a hurricane came through so roads were still closed and could not get out to the beach to see them
We did get T-shirts so that was a plus.
Dave ----
Last fall wife & I and 2 other couples went to the NC outer banks, wife wanted to see the wild horses but is was after a hurricane came through so roads were still closed and could not get out to the beach to see them
We did get T-shirts so that was a plus.
Dave ----
Lead Driver
Joined: Jun 2013
Posts: 5,651
Likes: 1,157
From: Tolland, CT
Did you get to see any whales? T-shirts are always a good thing.
Last fall wife & I and 2 other couples went to the NC outer banks, wife wanted to see the wild horses but is was after a hurricane came through so roads were still closed and could not get out to the beach to see them
We did get T-shirts so that was a plus.
Dave ----
Last fall wife & I and 2 other couples went to the NC outer banks, wife wanted to see the wild horses but is was after a hurricane came through so roads were still closed and could not get out to the beach to see them
We did get T-shirts so that was a plus.
Dave ----
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