Idles great, severe loss of power under load

Asked by ildiran961 Aug 25, 2022 at 06:00 AM about the 2000 Mercury Grand Marquis GS

Question type: Maintenance & Repair

I have a 2000 Grand Marquis and just replaced the intake manifold after it sat, not running for 18 months. The car starts and idles beautifully, but on the test drive, it lost almost all power when trying to accelerate. I'm thinking it's a clogged converter, but was wondering what else to check besides a vacuum leak. The CEL buld does work, but it hasn't come on and no codes are present (which is definitely confusing, considering how poorly it was running).

2 Answers
311,225

Gene answered 2 years ago

A vacuum leak will make the idle high on this type pf system so I doubt you have one. You can get a back pressure test kit from most parts stores for the exhaust, it can't run right if it can't breathe, also make sure the fresh air intake is not restricted.

2 people found this helpful.
Mark helpful
158,475

James answered 2 years ago

Also, after sitting for 18 months you might have water condensation in the gas tank. Put a bottle of Drygas or similar product in the gas tank and fill it up. Hopefully that's all it is. Hope that helps! Jim

Mark helpful

Your Answer:

Related Questions

  • Idles great, severe loss of power under load 2 Answers

    I have a 2000 Grand Marquis and just replaced the intake manifold after it sat, not running for 18 months. The car starts and idles beautifully, but on the test drive, it lost almost all power when tr...

    2000 Mercury Grand Marquis GS

    -

    Maintenance & Repair

  • 2003 grand marquis idles up and down, dies at stops, loud hiss under hood 1 Answer

    idles up and down, dies at stops, loud hiss when hood is open. ...

    2003 Mercury Grand Marquis LSE

    -

    Maintenance & Repair

  • unexplained loss of a/c freon charge after 2 weeks 5 Answers

    charge system add oil with dye pressures good nice and cold comes back 2 weeks later system empty no trace of dye anywhere has new evaporator compressor and reciever/dryer help???

    2005 Mercury Grand Marquis GS

    -

    Maintenance & Repair

  • Cable hanging under car 2 Answers

    What is this cable hanging from front to back under my car?? From the looks of whatever the issue is, it should be an easy fix, right???

    1999 Mercury Grand Marquis 4 Dr LS Sedan

    -

    Maintenance & Repair

  • A hose under the passenger side of a grand Marquis 98 1 Answer

    I had someone changed my tire on the passenger side of my 98 Marquis Grand Mercury and water came out of a hose that's on the passenger side I don't know what it goes to and I would like to know i...

    1998 Mercury Grand Marquis 4 Dr GS Sedan

    -

    Maintenance & Repair

Grand Marquis

Looking for a Used Grand Marquis in your area?

CarGurus has 394 nationwide Grand Marquis listings starting at $3,495.

ZIP:

Own this car?

Share your experience with others.

2000 Mercury Grand Marquis

Write a car review

Review another car

Shortcuts

Search Mercury Grand Marquis Questions

CarGurus Experts

  • #1
    Tracy Hooks
    Reputation
    9,920
  • #2
    Trippmeister
    Reputation
    5,180
  • #3
    Bob Beaman
    Reputation
    3,900
View All

Know more, shop wisely

Search

Related Models For Sale

Used Lincoln Town Car
10 Great Deals out of 506 listings starting at $2,999
Used Ford Crown Victoria
82 listings starting at $5,995
Used Toyota Camry
2,400 Great Deals out of 42,866 listings starting at $975
Used Ford F-150
6,489 Great Deals out of 171,395 listings starting at $1,800
Used Chevrolet Silverado 1500
4,169 Great Deals out of 116,871 listings starting at $2,500
Used Buick LeSabre
115 listings
Used Honda Accord
1,266 Great Deals out of 23,017 listings starting at $998
Used Chevrolet Tahoe
1,281 Great Deals out of 24,389 listings starting at $1,445
Used Ford Mustang
989 Great Deals out of 21,352 listings starting at $2,000
Used Lincoln Continental
19 Great Deals out of 453 listings starting at $7,995
Used Chevrolet Camaro
551 Great Deals out of 7,299 listings starting at $4,886
Used Chevrolet Impala
182 Great Deals out of 3,356 listings starting at $1,999

Used Cars For Sale

2008 Mercury Grand Marquis GS For Sale
27 listings
2007 Mercury Grand Marquis GS For Sale
28 listings starting at $3,495

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use. Content will be removed if CarGurus becomes aware that it violates our policies.