300 missing

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May 5, 2004 | 12:12 PM

GR8 1

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Joined: Aug 2003

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300 missing

My 1986 F250 has a miss in it when it idles. It makes my enginge jerk when its cold but when its warm you can still hear the miss in the exhaust.
What causes your engine to miss? I have replaced the distributer,spark plugs, spark plug lines. I'm guessing it misses because it's worn out, but I'm thought I would write this to make shure there was nothing else I could tend to.

1986 F250 double-low 4-speed 300-I6, 1brl carb

Last edited by GR8 1; May 5, 2004 at 12:16 PM.

May 5, 2004 | 12:16 PM

85e150

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Joined: Apr 2004

Posts: 34,475

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Checked the intake bolts? My '85 works loose on #1. Starts as a off and on miss, ends up constant miss. Temperature will change it at the beginning.

Good luck.

May 5, 2004 | 02:30 PM

oldhalftons

Postmaster

Joined: Feb 2003

Posts: 3,439

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From: Spokane WA

ANY vac leak will make a 300 miss and run bad.

the EGR gasket and the intake vacuum tree are prime suspects anytime a 300 starts missing all of a sudden.