20 Most Recent 1999 GMC Sierra 3500 Questions & Answers

check fuel pressure should be 42 lbs. check filter if low some engines have 2 filters

1999 GMC Sierra... | Answered on Sep 12, 2017

You can have someone stand by the truck and they should hear the pump kick on when you turn the key in the on position. Can you spray fuel into the throttle body and will it start that will tell you if the ignition is ok or not and also tell you if you have fire to the cylinders. If it start right up and shuts off you either have a bad fuel filter, fuel pump or a plugged catalytic converter in the exhaust system.

1999 GMC Sierra... | Answered on Jun 10, 2017

Stalling when the engine is running could be faulty spark.look for faulty cables also.
Change the plugs and cables if you have nt done that during last maintenance

1999 GMC Sierra... | Answered on Sep 08, 2016

The ignition module is under the distributor cap. Mark the spark plug wires location then remove the cap. Remove the 2 screws and connectors.

1999 GMC Sierra... | Answered on May 08, 2014

Replace with new bulb you must not touch the glass part of the bulb.oils from fingers will cause it to burn out, also make sure that there is no condensation inside of the bulb housing as this will cause the bulb to short out and possibly cause a fire

1999 GMC Sierra... | Answered on Apr 13, 2014

There are two ECM fuses - marked ecm 1 and ecm B.
ECM B powers the fuel pump and the Veh control module which handles most of the sensors.
ECM 1 powers the ignition module, coil, injectors and the rest of the engine sensors.
You may need a repair book with diagrams to check all of the circuits for shorts.

1999 GMC Sierra... | Answered on Jul 30, 2012

you have a wire grounding out somewhere. The only way I know how to find it quickly is not very safe and requires extra work later.

1999 GMC Sierra... | Answered on Jul 30, 2012

spark plug wires or coil pack

1999 GMC Sierra... | Answered on May 26, 2012

Yes, the system is called Passlock, and malfunctions regularly. Go to this link for an explanation of how it works, plus some tricks and tips on how to reset it, or bypass it.


1999 GMC Sierra... | Answered on Mar 27, 2012

For the ECM 1 fuse to open you obviously have a short to ground , start with the injector disconnected and see if ECM 1 fuse still blows.If it does disconnect crank sensor, also inspect wires for the injectors or any rub through wires here is a diagram cansmo_178.gif

1999 GMC Sierra... | Answered on Sep 09, 2011

The fuel filter may need to be replaced, but wont fix the problem you have. Its just a maintenance item that should be done every 15k miles anyhow. Check it over, check the large hose between the air filter and the engine make sure its secure. see if all hoses are ok, if you see/hear a vacuum leak. If all looks ok, time to have it checked by a shop.

1999 GMC Sierra... | Answered on Sep 01, 2011

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