Mercury Grand Marquis Problems

Engine Stalling and/or Hesitation on Acceleration due to Faulty Idle Air Bypass Valve on Mercury Grand Marquis

Problem Description and Possible Solution

If you experience difficulty starting the engine when cold, stalling at idle, or hesitations during acceleration, it may be the idle air bypass valve. This valve helps the vehicle idle steady when the accelerator pedal is not pressed.

(25 people reported this problem)

Mercury Grand Marquis Vehicles With This Problem

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Average mileage: 116,900 (13,000–160,000)
8 model years affected: 1990, 1991, 1998, 1999, more2000, 2001, 2005, 2006
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Viewing 1-8 of 8 comments
Engine turns over, but cuts off when I put it into gear. I have to sit with my foot on the gas pedal to keep it going. Usually, after 10-15 minutes - and several attempts - it will continue running when I take my foot off the gas pedal...then, I can go and it will keep running. Once in a while (1 in every 10-15 times) when I start it, it will immediately just run like it's supposed to.
When accelerating between 1st and 2nd gear, there is a lengthy shift time, also I notice when pressing slightly harder on gas pedal while already in travel, it is not responsive as a v-8 should be with quick acceleration. It seems as either gas is not traveling through the gas pump at the required rate, or after getting my intake replaced, that possibly one of the (pistons/cylinders) could be bad, or may have a compression leak. No smoke or stalls and no problems starting when cold. Thanks!
my car cuts off when i crank it but if i give it gas it will stay running Take my foot off it cuts off then crank back up
It act like it don't want to start then when it do it shakes and act like it want to cut off. Then when I start going it takes acouple secs to get to the next gear and to accelerate