Question about 1991 GMC Sierra

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When i plug in my map sensor on my 1991 gmc the truck stalls

Truck idles as long as the map censor is unplugged

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  • 436 Answers

Have you plugged in a new map sensor and this happens, or just the original one? Could just be a bad sensor. Also you could have broken /exposed wires that are shorting out.

Posted on May 11, 2014

Testimonial: "Ty. I have tried 3 different MAP sensors. Small town ordered new one. No mechanics here either. I am a carpenter so this mechanic talk is as hard as fixing it lol wiring looks fine."

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Posted on Jan 02, 2017

  • 1055 Answers

SOURCE: engine wont idle

replace the timing gear its wore out

Posted on Feb 18, 2009

  • 3600 Answers

SOURCE: Describe your trouble shooting 91 gmc truck

test fuel pressure by renting a fuel pressure test kit from schucks or auto zone then turn key on then off if it hits 50 psi it's ok if it drops below 20 psi in one minuter then fuel pump is bad. if it has throttle body injection then replace the injector or pull it apart to see if it is plugged.check oil pressuer switch behind the distributor to see if it is bad it will cause it not to run if defective.

Posted on Jul 18, 2009

  • 491 Answers

SOURCE: fails idle emissions test hc

High HC?
****** ignition timing....this will lower HC but raise other values during test.
Do you have room to increase other values?
After test return timing to the most advanced position without spark knock under load for best MPG.

Posted on Aug 11, 2009

  • 3 Answers

SOURCE: stalls at idle no fluxuation in voltage at iac

the throttle body is dirty, this will cause low charging system voltage and intermittant stalling. Push open the trottle plate and hose it out with throttle body cleaner. A tooth brush will help

Posted on Oct 19, 2009

  • 666 Answers

SOURCE: Engine runs rough, while running if the MAP sensor

then map is working, have you tried tune up?

Posted on Jun 09, 2010

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Related Questions:

1 Answer

Why does my truck stall when I plug in the map sensor?

If that's all you have to offer then I would say your map sensor is bad...

May 09, 2014 | 1991 GMC Sierra

1 Answer

My 1991 gmc sierra will start but i have to feather the gas if I can get it to idle, the MAP sensor needs to be unplugged. I have changed the MAP 3 times with spares I had around.

Changing parts is not a solution or fix

Testing a vehicle to find a problem is

Once a problem is found, then the solution is
usually there in front of you

It starts
Is the fuel pressure correct?
Feathering the gas,that would pertain to the TPS Sensor
Was that tested?
MAP-no control over that,do you have vacuum leaks
& were any of the maps tested & correct for your elevation
or vehicle specs

Spark Plugs Good
Rotor & Cap Clean
Vacuum Leaks?

Got an IAC Valve at base of throttle body to clean or replace?

May 10, 2014 | 1991 GMC Sierra

1 Answer

1993 gmc sierra 4wd runs rough after engine warms up.At stop lights she will stall out if i dont keep foot on break and give a little gas. any suggestions ?

Question, does this pickup blow black smoke on idle or at a stop sign. If so check your map sensor might be plugged up or unplugged or bad.

Mar 05, 2014 | 1993 GMC Sierra K1500

1 Answer

2003 sonoma shuts down when MAP sensor is plugged in

Could be a bad one even if its new it happens

Feb 25, 2014 | 2003 GMC Sonoma

1 Answer

1995 GMC Keep stalling Randomly

starter bendix sticking maybe

Mar 31, 2013 | 1995 GMC Sierra

1 Answer

Car starts runs as soon as you rev it up some it cuts out and dies replaced map censor computer and other censors and fuel filter

Try replacing the crank sensor and relearn the idle air control.The sensor is in the back of the motor.They tend to crack and this will cause stalling.Hope this helps.Good luck.

Mar 16, 2010 | 1990 Chevrolet Lumina

1 Answer

1991 302 runs like it is chocking out, I have changed the fuel filter, plugs wires rotor cap, and map censor, runs rough and worse when in gear, eating please? The truck is a 1991 f150 NITE 4x4

is it idling high and you put it i gear it runs rougher and smoke black check your coolant sensor also connection or sensor itself and fuel pressure if high check for return line blockage also vacuum leaks make sure you have the right vacuum going to your map sensor you need to check right vaccum at idle going to your map sensor/

Jan 19, 2010 | 1991 Ford F150

2 Answers


is the check eng lite on ?

Nov 15, 2008 | 1994 GMC Safari

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