Occasional miss

Discussion in 'Technical' started by Comet-73, May 5, 2006.

  1. Comet-73

    Comet-73 Member

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    My 302 is doing something wierd it misses at low rmps and only sometimes one time it will run fine then the next it will sputter and miss but only at low rmps i have no idea why
     
  2. Mavaholic

    Mavaholic Growing older but not up!

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    First thing I would do is get rid of the points and install a Petronix or some kind of electronic ignition.
     
  3. Comet-73

    Comet-73 Member

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    Ok sorry i forgot to give a little backround i did upgrade my ignition i have and new ford electronic dizzy a msd 6AL ignition, msd blaster2 coil, msd wires, and just some autolite sparkplugs. I also have a edlebrock intake holley 650dp comp 268h cam now it ran fine before on all this stuff except for the new comp cam i put the cam in it ran fine throught the break in then i had to pull the intake because i had a small coolent leak into the oil now when its all back togeather it runs great half the time there is no rhyme or reason why its missing as far as i can see its got spark at least when i check it. its got plenty of fuel aslo at least when i check it, its a manual choke so i know its getting air. Its wierd i can drive for hours and it run normal then out of nowhere it will start missing mostly at low rmps like under 1000 it will run fine at speed and it seems to get worse once it starts to the point where it stalls then i start it back up and it will run fine.
     
  4. Jamie Miles

    Jamie Miles the road warrior

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    Years ago my grandpa had a similar problem. It turned out to be a crack in the base of the carb. As the engine heated up, the crack would expand and create a vaccum leak.

    How old are your plugs?
     
  5. Comet-73

    Comet-73 Member

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    My plugs are about a year old with like 1000miles on them i dont drive my car in the winter so they sat for a couple months.

    It also does it when its warm or cold. i dont know its got me beat i checked my timing its ok its about 10degrees i reajusted my carb, check all the wires, checked everything i could think of it could be and yet it still does it.

    Ps could it be that my new cam is not fully broken in. i did the 30 mins at 2000-2500 the sheet said and have put about 25miles on it since.
     
    Last edited: May 6, 2006
  6. 1972Grabber

    1972Grabber Always Broke

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    Try taking your carb apart and see if you have some junk in the bowl or maybe junk in the jets.

    That is why I run a fuel filter before the gas goes into the fuel pump and I run a filter between the pump and the carb.
     
  7. Comet-73

    Comet-73 Member

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    clean as a whistle... in fact i have 3 fuel filters
     
  8. FoMoDave

    FoMoDave Maverick Owner

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    I would recheck EVERYTHING in the ignition. Where these all new parts? Maybe a loose/bad connection? Check that alt. is working right.
     
  9. scooper77515

    scooper77515 No current projects.

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    loose spark plug wire, or worn one periodically shorting against engine or frame. I had one that the header had burned through a boot and periodically shorted and missed.

    There could be quite a few places where you pick up a miss, and really, just need to check everything.

    OR, call it a "lope". I originally had two stuck lifters and it was only running on 6 cylinders, and sounded really good and lopey. Stunk to high heck, and poor accelleration, but sounded good at idle.
     
  10. Comet-73

    Comet-73 Member

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    I check my msd box i think it might be it un hooked it and ran without and it hasn't done it yet but i dont know yet sometimes it would be hours of driving before it did it.
     

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