20 Most Recent 1996 GMC Sierra Questions & Answers

They are located UNDER the Intake Manifold (Spider Assembly)...

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1. Oil coming from the ext. vent means Overfill fluid transmission or valve body problem (need to open the transmission to overhaul it) but usually overfill. 2. Do you have any transmission faulty code 3. If you pull a trailer, heavy load there is a function in PCM (powertrain control Module) that raise the pressure to compensate the slip at clutch pressure and if you unhook the trailer and go on the highway before the PCM learn it, it will shift hard. What GM call the "shift adapt". You probably have a 4L80E for transmission or the 4L60E depends on the truck's options. hope it helps.

run the fault codes could be a problem crank/cam position sensor or bag ground wire connections

You may have a dead cell in the battery , or damp in the electrics.

What is the voltage on the battery ? If it's not in the 13.5 volt range the battery is not charged. What does the battery read when you try to crank ? It should be in the 10.5volt range. Get a set of jumper cables. Hook them up correctly and see if it cranks. If it does - the battery is not fully charged or it's a bad battery. A car battery can produce enough amps to light lights and other small stuff but not produce enough amps for the starter to turn over the engine.

Output speed sensor needs replacing

The heat cut's out ? The heater blower motor stops working ? Testing the electrical circuit would be the proper way to diagnose . Looking at a wiring diagram an using a DMM - digital multi-meter , an doing amp draw test on the blower motor . The PRND321 an blower motor probably share a ground or power point . Looking at a wiring diagram for both circuit's would show that . Not a short , more likely a loose ground connection . Free wiring diagram's here http://www.bbbind.com/free_tsb.html Enter vehicle info. year , make , model and engine size . Under system click on HVAC then under subsystem click on HVAC controls . Then click the search button ,then the blue link . First blue link is blower motor control circuit . Voltage drop test the blower motor ground .Videos on youtube showing how to diagnose ! Blower Motor Resistor Replacement Wire Splice Splicing Amperage Draw Test Blower Motor Resistor Function and Diagnostics Mastering Voltage Drop Testing with Pete Meier and Jerry Truglia

Probably the high pressure switch on the accumulator - try disconnecting the connector and jumping the pins to see if the clutch will engage. If that is the problem, DO NOT leave it jumped - replace the switch. If that is not the problem, you will have to check the clutch wiring, relay and fuse for continuity back to the HVAC controls. If that is OK, the problem will probably be in your HVAC control module.

I would check a few things: Load test the battery. If its got any age on it at all, this could be the culprit. Test the starter. Check for loose connections at the distributor cap. Make sure the rotor in the cap is seated and that the cap is properly seated. Check for loose connections on the battery, the starter and make sure you have fuel pressure on the injector rails (key on, detent the shrader valve .. you should get fuel).

They make oil pan plugs for this situation. It's a bolt with a rubber spacer that expands to seal the hole when you tighten it. If the old plug is still in the pan, use vice grips to thread it out. No need to replace pan, but maybe replace the oil change shop. Guys you went to have no experience.

If the throttle cable is not attached properly to the throttle body or you have a bad motor mount, the throttle cable may be pulling the throttle open as you shift into gear. Open the hood, find the throttle cable on the throttle body. Inspect how it is connected and also how the cable is fastened in the engine comoartnent. Next, watch what happens as someone else starts the truck and puts it into gear. If the engine shifts significantly, check for broken motor mounts. If the throttle cable is misbehaving, correct the installation.

Possibly a busted fuel pressure regulator diaphragm. The regulator is mounted to the end of the fuel rail. With the engine idling, pull the vacuum line off the regulator port. If gas comes out of the port, replace the regulator.

Something wrong in the fuse box if you only have .4 volts at the fuse. Maybe a loose terminal in there.

try a quality injector cleaner if EFI or clean carby otherwise missing is more from injector problems than spark plugs