460 4bb carb skipping and bucking around 2000 RPMs

Tiny
DHRACER6061
  • MEMBER
  • 1987 FORD F-250
  • 138,000 MILES
The truck normally idles decient but today there was a slight pop every minute or so and when speeding up in 2nd or 3rd gear around 2000 rpms it hesitates and bucks almost like a rev limiter but also back fires alot.
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Thursday, October 10th, 2013 AT 8:45 AM

8 Replies

Tiny
HMAC300
  • EXPERT
Check for a fouled or bad spark plug or wire. Might be a distributor cap as well.
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Thursday, October 10th, 2013 AT 9:33 AM
Tiny
DHRACER6061
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My cap and wires are new what should I look for if the plugs are fine
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Thursday, October 10th, 2013 AT 12:32 PM
Tiny
HMAC300
  • EXPERT
You'll have to first find the cylinder/s that are doing it if possible but check intake manifold vacuum if 15" or below check for a plugged exhaust. Then have the carb checked it may be a power valve or accelerator pump bad. Or is the carb new as well? If it's a newer carb then forget that what I said. If it's an older carb then think about a rebuild due to the alcohol in todays fuel. If it's a carb problem it usually sounds like a spit instead of a backfire kinda hard to describe on here cause we can't hear or make sounds.
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Thursday, October 10th, 2013 AT 12:46 PM
Tiny
DHRACER6061
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I checked all the spark plugs they were fine but now it won't start. It just cranks and cranks spent even sound like its sparking
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Thursday, October 10th, 2013 AT 1:52 PM
Tiny
DHRACER6061
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Doesnt even sound like its sparking
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Thursday, October 10th, 2013 AT 1:54 PM
Tiny
HMAC300
  • EXPERT
Check pick up coil resistance in dist, shoud be in the area of 400-800 ohms then pul module off and have auto parts test it or do this test
Disconnect and inspect control module 4-wire connector from coil. Disconnect ignition coil connector from coil. Attach an ohmmeter lead to distributor base and the other to "TACH" terminal of ignition coil connector.
If reading exceeds 100 ohms, replace control module. If reading is 100 ohms or less, inspect wiring harness between control module and ignition coil. After test, connect ignition module and coil connectors.
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Thursday, October 10th, 2013 AT 4:31 PM
Tiny
DHRACER6061
  • MEMBER
Ok I'll try that. Thank you very much. And one more question I've heard of putting a gm style dist on my engine before how do I go about doing that
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Thursday, October 10th, 2013 AT 5:54 PM
Tiny
HMAC300
  • EXPERT
No idea, yours is old that's all it's not a bad system. Besides your oil pump drive is different than a gm anyhow you wold also need agm with a vacuum advance like yours.
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Friday, October 11th, 2013 AT 5:44 AM

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