intermittent miss (scattered, not just 1 cylinder)

1986 MERCURY SABLE STATION WAGON
125,000 MILES
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LARRY P
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  • 1 POST
Have 2 canadian-built ford wagons ('86 and '89). both have 302pfi engines. both exhibit an intermittent miss at light load (particularly after the trans shifts) which is much more pronounced when warm. have replaced just about everything in the ignition system, tried disconnecting the egr valve, cleaned the iac motor, all to no effect. strange thing is, the problem will disappear for a day, a week, or a month and suddenly return with nothing having been done to the car. absolutely stumped. any thoughts? thanks in advance.
Jul 20, 2012 at 7:57 PM
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KHLOW2008
  • ASE Certified Mechanic
  • 41,814 POSTS
  • ASE Certified Mechanic
Symptoms indicates the problem most probably is related to the ignition spark system and more likely a loose connection somewhere rather than a bad component.
Jul 21, 2012 at 2:04 PM
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