Top 20 1989 GMC K1500 - Page 2 Questions & Answers

Check the vacuum modulator and the hose going to it. Also check for vacuum leaks on or around the engine. Have you checked the fluid level or changed the fluid in the transmission? How about the throttle position sensor? (if it has one).

one element is for brakes/turn the other one on the same bulb is running lights how ever the part about brake lights go threw the turn signal switch the turn signal switch has diodes in it so that both rear light don't light up when turning i hope my explenation helps and yes some years gmm had bad tail light circuit boards you can test the connector at the lens housing with a test light there is also a plug connector where the bed meets the frame in the rear

It usually does this from lack of fuel and or air. When is the last time you replaced the fuel pump. I did a GMC once that was so bad it would only do about 15 miles an hour. Once the filter was changed it was like a new truck. Fuel filters clog up, it will still give you the pressure , but not the volume.

Are you a TBI?(throttle body injector) if you are take the top of the air cleaner out step on the gas pedal(do this in park hood open fire extinguisher on the ready.) does it backfire through the air cleaner if it does you are in need of a whole distributor unit the distributor unit has a relector that has a high tendency for failure by the way the vehicle sound there is only 2 possible problems you coil is faulty and this includes the connection to the coil which has a tendency to seperateor the connection to the ICM.(ignition control module where the coil is) or the whole distributor reluctor

Drive your truck to get the light to come on find a place to pull over and read the codes. Here is how >> link to page

i have a 1988 k1500 seirra truck, that will idle fine then it will choke its self out and stall out.(i have a new egr synolyd,new egr, a 1992 ecm pulled from a junk yard,new cap,rotor, plugs wires,distributorand, a new coil,,map sensor,and a 2 year old tps sensor; and the copression is 140- 155 in all cylinders), but it wont say running, what can i look at next to help it run and stay running?

when mine was pulling up the code it pulled a 12,33, and45

Check in backside of the top peddal brake.

You can ground it pretty much to any existing bolt on the frame. If the area you choose is painted, sand it down to the metal for good continuity and you're set.

Check the coil, the control modual in the distributer, and the ecm. thats what controls the injectors.

If you didn't replace the Throttle Position Sensor, check the adjustment on that. Also, pull the Idle Air Bleed Valve and clean it.

you need a pickel fork like a big chesel with a hole in it and steering wheel puller

Change the fuel filter.

Yes it will bolt right in.

change the fuel filter and check the timing .

if the pully's are the same size it will probably fit alout of chevy parts will interchange with each other unlike ford. thanks

IT HAS TO TO BE PRESS ON OR JUST BUY A NEW ONE IT WILL BE BETTER TO BY ONE BECOSE WILL HAVE PAY TO HAVE IT PRESS ON ,..........

On an 89' with those symptoms i wouldn't rule out plugged exhaust either as in catalytic converter.
Make sure it's breathing good. Another sign is excessive fuel usage, or worsening gas mileage as well.

i think you just un hook the battery thats what you do in my 05

its on the colum

Hello, I have a 1991 GMC Sierra, I did the same thing as you described and mine does the same thing. Speaking to a Mechanic about this I was told it is normal as long as it fluctuates and does not constantly flow out. If it constantly flows out then service will be needed to pump/radiator soon.