1990 Mercury Marquis Engine Missing

1990 MERCURY MARQUIS
110,000 MILES • V8 • 2WD • AUTOMATIC
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MIKE PERRY
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  • 1 POST
Good Day

I just got this car recently and put plug wires, cap,roter, plugs and fuel filter. When the engine and trans get hot like about 15-20 minutes on the road it starts missing, not a single cyilinder miss but an all miss like a chugg or hesitation.
This seems to happen when the engine loads up like when its shifting from 2nd to 3rd gear or climbing a grade in overdrive.


Please give me some things to look at.
Thanks I appreciate any info you can help me with.

Mike
Aug 13, 2008 at 10:30 AM
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2CARPRO JACK
  • CERTIFIED EXPERT
  • 11,533 POSTS
Need to check fuel pressure when hot and quality of spark when engine is hot.Both can be affected by heat and will do what you describe. Has the check engine light ever come on?If so have it scanned for codes, may help lead in the right direction
Aug 14, 2008 at 8:18 AM