20 Most Recent 1998 GMC Sierra - Page 9 Questions & Answers


Testing of the fuel and ignition systems is in order. Intermittent problems need testing when the problem is present, otherwise it won't help find the problem.
I would start by checking for spark on a spark plug wire (or two or three plug wires, in case it may be a bad coil), during those times when it won't start. You need to see a blue, snapping spark to verify ignition system is working.
To check the fuel system, have the fuel pressure checked, and the injector circuit checked. Good that you hear the pump, but you don't know if fuel pressure is correct, or if fuel is getting into the cylinders. One short test is to spray starting fluid or carb cleaner into the intake while engine is cranking. If engine fires up for a few seconds, you know it is a gas related problem.
If ignition system is the intermittent problem, could be failing coil or coils, ignition module, crank position sensor, even the computer, or a wiring problem like a bad connection. Testing of each component will be required, or you could start throwing new parts at it, like many people do, until you find the bad part. Find a reputable mechanic-there still are a few, lol.

1998 GMC Sierra | Answered on Aug 01, 2013


You can remove the front bed bolts & loosen
the rear ones,& tip up the bed or remove the
tank straps & drop the fuel tank
You Tube Video has the procedure to watch

1998 GMC Sierra | Answered on Jul 13, 2013


Sounds like a bad crank position sensor or a bad camshaft position sensor.... If the sensors can't tell the ecm where the position the crankshaft or camshaft is, the ecm won't know when to send a spark. So the ecm won't send any spark.

1998 GMC Sierra | Answered on Jun 22, 2013


Is the base fuel pressure the same hot when it is cold, and so is the spark weak when the engine is hot ?

1998 GMC Sierra | Answered on Jun 17, 2013


Are you loosing power to the fuel pump, or spark to the plugs ?

1998 GMC Sierra | Answered on May 15, 2013


I had a 1997 Chevy c1500 pickup and it did not fire. Turns out the ground wire from the battery was bad. Replaced it and runs fine now.

1998 GMC Sierra | Answered on Apr 23, 2013


Check the distributor cap and rotor for worn or corroded terminals,cracks and burn marks.

1998 GMC Sierra | Answered on Apr 21, 2013


low on oil the first time now the valve lifters are worn

1998 GMC Sierra | Answered on Apr 14, 2013


To check the fluid there wil be a plug on the side of the Reese diff housing. Use w 3/8" ratchet to remove the plug. The fluid should be level with the button of the hole. To change the fluid first remove the fill/check plug as described above. You always want to make sure that plug comes out first so you know you can fill the diff after your done. Then place a drip pan under the read diff and remove all the bolts that hold the diff cover top the diff housing, roughly 10-12 bolts. Then carefully pry the pan away from the housing. Let the gear lube drain while you cean the gasket meterial from both the cover and the differential housing. You can either get a new gasket or you can use a good RTV type gasket maker. I prefer the higher end GREY products myself. Lay a pencil size bead around the differential. Reinstall the cover tightening the bolts to just barely snug. The RTV should just start to push out from behind the cover. Let it sit for about a half an hour and then do the final tightening. I am almost 100% positive that the rear diff talks regular 80/90 weight gear lube. Your local parts store will be able to conffirm the correct lube and the quantity, approximately 2-4 quarts depending on what size ring gear you have.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

1998 GMC Sierra | Answered on Apr 11, 2013


I wonder if the buzzing is coming from the key switch ? (ignition ) . CTSY is always HOT ! you need a wire diagram to see where CTSY wires travel to & from to isolate this draw . I found that the CTSY 20amp fuse is also wired to the parking lights 20A fuse @ fuse block . start there, check all wires, grounds to parking lamps, and switch, it might be your headlight switch thats causing your problem ! replace it and see what happens !

1998 GMC Sierra | Answered on Mar 24, 2013


usually a sudden stop is sensor gone out if it fuelor timing it would have erratic or skip tostart with i would put it on a diagnostic tester to be sure

1998 GMC Sierra | Answered on Mar 14, 2013

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