Car doesn't stay running

Tiny
FISHMEYER
  • MEMBER
  • 2001 MERCURY MARQUIS
  • V8
  • 2WD
  • AUTOMATIC
  • 89,000 MILES
My father in law has a 2001 Mercury Grand Marquis with 89000 miles. The car will start up without any problem, but then dies when you put it in gear. It will idle ok some of the time, but other times it will die. As it is dying the battery light comes up, but don't think this is an issue. What would you think?
Thursday, December 30th, 2010 AT 5:15 PM

6 Replies

Tiny
LEGITIMATE007
  • MECHANIC
  • 5,121 POSTS
Well you are putting a load on the electrical, so the battery and the alternator will need to be checked, also check your IAC(idle air control valve). Could be faulty or just dirty.
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Thursday, December 30th, 2010 AT 5:22 PM
Tiny
LEGITIMATE007
  • MECHANIC
  • 5,121 POSTS
https://www.2carpros.com/articles/how-to-check-a-car-alternator
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Thursday, December 30th, 2010 AT 5:23 PM
Tiny
FISHMEYER
  • MEMBER
  • 2 POSTS
How do you check the IAC or clean it? Thanks.
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Thursday, December 30th, 2010 AT 5:30 PM
Tiny
LEGITIMATE007
  • MECHANIC
  • 5,121 POSTS
You have to take it out of its bore, which is located on the throttle body, by the way you will clean the throttle body while your at it, you will need help because someone will need to turn the key on(not start)and you will observe if the "pintle of the iac moves in and out, like little steps. If it moves in and out, then it should be fine.
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Thursday, December 30th, 2010 AT 7:43 PM
Tiny
GLORIA PRATT
  • MEMBER
  • 3 POSTS
Somebody asked how do you clean the IAC on 99 Mercury Grand Marquis? I want to know.
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Tuesday, January 7th, 2020 AT 4:43 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Hello,

Here is a guide to help you step by step and the location if the IAC in the diagrams below for your car:

https://www.2carpros.com/articles/idle-air-control-valve-service

Idle Air Control (IAC) Valve On center rear of engine, near left side of intake manifold.
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Friday, January 10th, 2020 AT 10:53 AM

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