1993 MERCURY GRAND MARQUIS.

  • Tiny
  • dobybears
  • 1993 Mercury Marquis
  • 100,000 miles

Have taken 2 recent trips of 500 miles. When I get to around 300 miles, the car starts bogging down and will not go over 45 mph. It will snap out of it for awhile, then bog down again. While it is doing this, it uses twice as much gas as usual. When I get diagnostic reading at the parts store, all they can tell me is it's a fuel problem but cannot find specifics. Any ideas

Friday, November 4th, 2011 AT 11:46 PM

6 Answers

  • Tiny
  • fixitmr
  • Member

So the CEL does not come on? What motor is it?

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Saturday, November 5th, 2011 AT 3:10 AM
  • Tiny
  • dobybears
  • Member

It's a v8

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Saturday, November 5th, 2011 AT 4:21 PM
  • Tiny
  • cadieman
  • Member

You need to know the fuel pressure when this happens. Also remove the o2 sensor to check for a pluged exhaust.

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Saturday, November 5th, 2011 AT 4:32 PM
  • Tiny
  • fixitmr
  • Member

So it only does this on long trips? Is it all highway (300)?

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Saturday, November 5th, 2011 AT 5:11 PM
  • Tiny
  • dobybears
  • Member

Yes, it is only on long trips on the interstate. It seems to run fine in town. But after driving 300 miles non-stop when it's getting down to about 1/4 tank of gas, that's when it starts bogging down.

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Sunday, November 6th, 2011 AT 6:14 AM
  • Tiny
  • fixitmr
  • Member

I'm thinking it could be an EGR valve issue? Or fuel pump issue?

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Sunday, November 6th, 2011 AT 4:46 PM

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