20 Most Recent 1993 GMC Sierra Questions & Answers


When this truck dies,does it have spark,or fuel pressure?Check it for no spark,if it has no spark,replace the ignition module.These gm year models are bad to go out ,and the distributor pick up coil also.Replace the module first,if this does not help,replace the pick up coil.NOW ON A FUEL RELATED PROBLEMit could be fuel pump,fuel pump relay,or the pick up coil.The pick up coil pulses the injectors,and the spark.I hope this helps,if not let me know.

1993 GMC Sierra | Answered on Apr 29, 2018


probably a brake light switch at the top of the brake pedal arm feel up there till you find a white or black plastic switch. They are inexpensive at Am*zon or Rock Auto.

1993 GMC Sierra | Answered on Jan 24, 2018


sounds like a vacuum leak from a mad gasket
as the engine warms up the gap increases allowing the noise
on acceleration the vacuum is very low so the noise is not heard
check for hoses that are cracked , loose or fallen off

1993 GMC Sierra | Answered on Sep 09, 2017


The switch inside the steering column is broken. You can repair it if you are a little bit talented with tools .Buy your self a repair manual specific to your model and year. it will show you step by step Chilton or Haynes produce these for $25 any auto parts store. or better yet buy a factory repair manual for your truck but expect to pay $150 plus for it.There is a Factory "Service Manual" and a Unit Repair" manual the later is the one you want.

1993 GMC Sierra | Answered on Jul 22, 2017


There's probably something in the way. Get under and behind the seat with a flashlight and check the back end of the rails to see if something is there.

1993 GMC Sierra | Answered on Jul 09, 2017


first off --run the fault codes
it could be a wiring problem, TCM , or VSS problem, oil change needed or transmission actuator problem

1993 GMC Sierra | Answered on Jun 20, 2017


Once upon a time... half a century ago...

Carbureted engines had a hard rod between the throttle... and a Vacuum dashpot that FAIRLY EFFECTIVELY... signaled those
transmissions when to shift...

Likewise... when those same carburetors were out of whack...
Those old time (not so bad) engines were equally bogged down...

Probably not as efficiently...

All the new electronic bells & whistles are merely
relating INTERREALATIONS we already know...

So when you say you remove the foot from the "gas"
the VACUUM CLIMBS... the tranny shifts

AS IT SHOULD...

You know the trouble is the MANIFOLD PRESSURE or
the transmission control module (TCM)...

The choice which to try first is doubly EASY...

COST & DIFFICUTY of the MAP is easy & low.

If that guess is wrong you know to label the
MAINIFOLD AIR Sensor as a GOOD SPARE...
AND move on the TCM.

Principles remain the same...

Cheapest & easiest first...

Hope this helps!!!

1993 GMC Sierra | Answered on May 24, 2017


I would check the engine timing and do a check on the exhaust to be sure it is not partially blocked. As to the snapping when you shift I would check the universal joint to be sure it is ok and the rear end may have some play in it.

1993 GMC Sierra | Answered on Apr 29, 2017


Google "DAYCO serpentine belt routing guides"

1993 GMC Sierra | Answered on Dec 09, 2016


I don't know about your particular application, but I do know that manufacturers are not using heavy enough wire for many things on a vehicle. So if the coils are bigger (higher output voltage) then they probably would draw more power and more load on control modules. I don't know any reason why stock would not be enough spark, these are a lot more powerful already than ignition systems were 40+ years ago. So in my opinion, no I wouldn't do it.

1993 GMC Sierra | Answered on Dec 03, 2016


look at your gauges if you go low on fuel it will come on also check oil ,coolant level also check the battery or volt meter if low or high will set it off

1993 GMC Sierra | Answered on Aug 30, 2015


Check that the EGR vacuum solenoid is working. Remove the vacuum line to the EGR and there should be no vacuum in that line with the engine at idle.

1993 GMC Sierra | Answered on May 22, 2015


I'm having the same problem at the shop I work for. So far I've changed the computer chip in it, throttle position sensor, and it seems to be doing better. Haven't found the real exact problem yet so if it fixes it let me know please. Chip is about $80 from Autozone and tps about $40 or $50.

1993 GMC Sierra | Answered on Apr 17, 2015

Not finding what you are looking for?
Cars & Trucks Logo

488 questions posted

Ask a Question

Usually answered in minutes!

Popular Products

1998 GMC Sierra
1998 GMC Sierra

971 Questions

1997 GMC Sierra
1997 GMC Sierra

824 Questions

2000 GMC Sierra
2000 GMC Sierra

661 Questions

1999 GMC Sierra
1999 GMC Sierra

584 Questions

1994 GMC Sierra
1994 GMC Sierra

587 Questions

Top GMC Experts

Marvin
Marvin

Level 3 Expert

85206 Answers

Jonah Oneal

Level 3 Expert

14092 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22484 Answers

Are you a GMC Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

View Most Popular

Sierra GMC

  • Sierra GMC

Most Popular Question

mytruck bad high low idle problem

  • Cars & Trucks
Loading...