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GMC preventive maintenance repair questions and answers

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  • Gmcgirl
    Gmcgirl - 1993 GMC C1500 - Preventive Maintenance - 3/16/2015
    Stalling, jerks what to do next
    I have a 1993 gmc Sierra 4x4 350 5.7l My truck runs fine when I start it up. After a few minutes it wants to stall, jerks on acceleration, and wants accelerates when you have your foot on the break. I have already replaces the spark plugs, fuel filter, fuel pump, ...
    • Jimm
      3/16/2015 Jimm
      First step - have the stored fault codes or check engine light scanned - for free - at any local auto parts store; Advance Auto, Auto Zone, NAPA. Then, post a reply as 'add answer' with the specific code for more assistance. There may be a fault code stored in the OBD memory which may not be displayed as a check engine light.

      Do not skip this important first step - there are literally hundreds of possible fault codes. Avoid wasting/ throwing money at the problem.

      Possible Causes of Engine Hesitation or Stumble:

      Dirty fuel injectors (cleaning the injectors often fixes this)
      Dirty air filter (change filter)
      Dirty / clogged fuel filter (change filter)
      Bad MAP (manifold absolute pressure) sensor
      Bad TPS (throttle position) sensor
      Bad or dirty MAF (mass airflow) sensor
      Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
      Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
      Bad gasoline (fuel contaminated with water or too much alcohol)

      Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

      Dirty or worn spark plugs
      Bad plug wires
      Weak ignition coil
      Wet plug wires
  • ajm
    ajm - 2006 GMC Envoy - Preventive Maintenance - 1/22/2015
    When I turn on the blower the air flow seems restricted
    The blow motor is running and heat is generating however the air flow from the vents appears to be restricted. Dealer is stating that there is nothing wrong with it however if I have the blower running at 5 the air flow coming out of the vent it should be blowing a ...
    0 answer
  • Tevon
    Tevon - 1998 GMC K1500 Suburban - Preventive Maintenance - 1/22/2015
    Why I don't have a smooth ride in this truck.
    159000 miles. When driving I feel when I go over any small or other bump. I'm not sure if it's shocks or suspension that should serviced.
    0 answer
  • Tevon
    Tevon - 1998 GMC K1500 Suburban - Preventive Maintenance - 1/15/2015
    One headlight starts out dem and there is a buzzing sound.
    157000 miles. Sometimes this happens at start up. I switch lights an bright lights on and then off an the buzzing goes off. I have daytime running lights.
  • jeff sullivan
    jeff sullivan - 2002 GMC Sierra 1500 - Preventive Maintenance - 1/15/2015
    Licence plate lights are out
    also passenger door does not lock when electric button is pressed and temp guage/compass on rear view mirror is dim and radio does not remember preset stations?
    • jdl
      1/15/2015 jdl
      As far as the tag lite, maybe the bulb is faulty? If not, have to check voltage and ground for lite, go from there.

      As far as passenger door lock, Your saying it won't operate using driver side master switch? If so maybe master switch is faulty, also check wiring on hinge side of driver door. Check the proper wire color for voltage to passenger side door lock. Also check the proper wire color on the hinge side of passenger door.

      For the radio, I'd check all voltage and ground circuits, if that checks out and no codes for the sound system, I'd have to suspect the radio, itself. I'm not sure about rear-view mirror?
  • wscanland
    wscanland - 1988 GMC K1500 - Preventive Maintenance - 12/10/2014
    Why won't my truck turn over when I turn the key?
    At first I thought it was from a gas leak draining all my gas out, but even when I put more gas in it it still won't crank. I check the fuel pump fuse and it wasn't blown. My lights don't dim when I try to crank it so I know it's not the battery. What could be the ...
    • Teddy B
      12/10/2014 Teddy B
      You don't know it is not the battery

      If there was current flow when you turn the key to start
      you would see a dimming of the lights,not the other way around as your said

      The dash lights should go dark when you are cranking also

      So have the battery tested
      It has to be good & take & hold a charge & have 12.6 volts
      No need to jump it,not a real safe practice at all

      Next check your cables & then have the starter tested

      You have a No Crank or a No Start?

      Adding fuel has nothing to do with the starter turning the motor over

      On a 2004 or newer vehicle then fuel load is a different issue in many ways

      May have a failed ignition switch or neutral switch or other problems

      Only proper testing will find a problem
  • goodcat
    goodcat - 2007 GMC Yukon XL 2500 - Preventive Maintenance - 10/26/2014
    Spare parts mechanics scheme
    Mechanics planned cut parts for a car with a private code to each piece and its name
  • AutoMD Member
    AutoMD Member - 2003 GMC Sierra 1500 - Preventive Maintenance - 8/11/2014
    Air condition are becoming heat air , why ? please help !
    It's 111,000.miles . It's happen even when it's cold or warm . even driving and stopped . any time after I'm turn the air condition on . a week a go . at my company . the check engine is not on . have no any warning light on .
    • CVO
      8/11/2014 CVO
      1. The blend door actuator is a servo responsible for controlling the mix of warm air from the heater core and cool air from the A/C and outside. If it malfunctions, your climate control system may not respond properly when you change the temperature on the climate control system.

      Both the manual and the automatic systems use this servo to control the blend door. If your ATC system fails to automatically change temp, this is also an indicator that the servo has failed.

      2. information showed this vehicle has a vacuum heater water control valve. If the control valve failed to shutoff, the hot coolant could have been circulated to the heater core.Check it as well.
  • AutoMD Member
    AutoMD Member - 2004 GMC Envoy - Preventive Maintenance - 8/6/2014
    Why does my key get hot?
    After running my envoy for 30 min i turn it off and the key is hot. What could cause this?
    • CTB1053
      8/6/2014 CTB1053
      There have been several recalls from GM recently about ignition cylinder issues. I would contact a dealer. You may get it fixed for free.
  • AutoMD Member
    AutoMD Member - 1996 GMC Jimmy - Preventive Maintenance - 7/31/2014
    Gage's quit working and won't start
    Half of my fuses have no power , scanner says no data link ,help please
    0 answer
  • AutoMD Member
    AutoMD Member - 1996 GMC Jimmy - Preventive Maintenance - 7/14/2014
    Battery was dead this morning. It took several tries to get the jumper box to turn it over.......
    What would cause that battery to go dead overnight, and does that mean I need to change the battery for a new one, because there was nothing left on that would have drained it overnight...But, we've had some extremely hot temps here in Az.
    • jdl
      7/14/2014 jdl
      Make sure the battery has a full charge. Also, check the charging system. Check battery and alternator connections and cables. Some of the national brand auto stores will check these systems for you. Some of these stores will make house calls, if you live close enough.

      You could also check for excessive amp draw, everything off. Generally, it shouldn't be more than 50 ma, that is .050 not even a tenth of an amp. If you have a digital multimeter you can do some testing, yourself.
  • AutoMD Member
    AutoMD Member - 1996 GMC K1500 Suburban - Preventive Maintenance - 5/12/2014
    My a/c has a weak flow out of my front upper vents lower works great and everything else blows fine.
    Rear controls works and heat blows great out of those front uppers. After 20 minutes or so the truck is cooled off and comfortable but I like it blowing in my face and summer is coming and I wanna address the problem quickly.
    0 answer
  • AutoMD Member
    AutoMD Member - 2002 GMC Envoy - Preventive Maintenance - 4/25/2014
    Replaced temp actuator got it working but still no heat
    it was the passenger side actuator I replaced. the driver side works fine. any ideas on what to check next
    0 answer
  • AutoMD Member
    AutoMD Member - 1980 GMC C1500 - Preventive Maintenance - 3/23/2014
    1972gmc c10 350 5.7 need procedure on stabbing dist.and timing alignment
    I need foolproof steps to align timing to stab dist.
    • Jimm
      3/19/2014 Jimm
      Need more information - is the distributor out of the engine, and you need basic instruction for the reinstallation - and timing of the engine and distributor - is this correct?
    • Jimm
      3/19/2014 Jimm
      If yes, then here are the specific steps;

      1) Remove the number 1 spark plug from the number 1 cylinder

      2) Rotate the crankshaft to align the timing marks (crankshaft pulley to the timing scale) - at the same time - be sure the number 1 piston is at TDC (top dead center) - with no valves; intake or exhaust - open.
      This piston position is critical because the distributor installation and alignment is based on the number 1 cylinder and piston at TDC on the compression-to-power stroke. Recall the four stroke engine has; intake, compression, power and exhaust - cycles or strokes.

      3. Once the piston is confirmed at TDC on the compression stroke - with the number # 1 spark plug removed (using a flashlight to observe or slim screwdriver to 'feel' and confirm the top of the piston) - then install the distributor so that the ignition rotor is pointing to the number 1 plug wire position on the distributor cap. This may take several tries with the distributor gear teeth so be patient - especially with the distributor drive gear as helical design - the distributor shaft will tend to rotate as the distributor gear is engaged on the camshaft gear and as the distributor is lowered / pressed into place.

      4. Leave the distributor hold-down clamp loose enough to be able to rotate the distributor - and snug enough to enable the distributor to maintain position. This step is required to obtain the final timing setting using a timing light according to the specification at base engine idle speed; 600 - 700 RPM - for example.

      5. That is it - reinstall the number 1 spark plug and replace the spark plug wire.

      If the ignition system; plug wires, spark plugs, coil - are all OK - then with a charged battery, strong spark and fresh fuel with all vacuum hoses conencted - the engine should start. As long as the base timing is correct - it should take no more than a slight twist or rotation of the distributor housing to have the engine start and run.

      You may reference the 'How-To-Guides' feature 'How to Replace a Distributor' on the AutoMD website for the specific steps to install and adjust the distributor for the base engine timing.
    • John's Auto Repair
      3/23/2014 John's Auto Repair
      What is stabbing the distributor suppose to mean?
  • diana
    diana - 2003 GMC Sierra 1500 - Preventive Maintenance - 2/20/2014
    The battery light is on says not charging when I start it in the morning. Goes normal after 1/2 hour.
    Normally needle is 1/2 way, straight up. Now it's at quarter way and dropping as I drive for the first while. What's up with this.
    • HouseCallAuto
      2/20/2014 HouseCallAuto
      Confirm the low charging voltage with a voltmeter across the battery. Replace the alternator
      3/1/2014 diana
      Thanks! It was alternator.