Question edited for clarity.
Question moved to model category.
3: 1988-95 5.0L, 5.7L and 7.4L Engines Firing Order: 1-8-4-3-6-5-7-2 Distributor Rotation: Clockwise.
Depending on where you connected power to the stereo from on the fuseblock you could be messing up the tranny. Refer to the manual versus where the stereo wires are, Worst case, disconnect power to the stereo to see if that's the cause of the problem.
Sounds like the starter solenoid or the starter itself - probably needs replacing but check the wiring at the starter first (loose connection, frayed wires, etc.).
Retarding the timing will cool the combustion which will lower the Hydrocarbon number,it will run bad but after a passed e test put the timing back to an advanced state which may help with the stumble.
First check for a vacuum leak. Any small loose hoses in the engine compartment? If not, suspect the idle air control valve. I have pasted test procedures for the iac below. Be careful not to confuse the tps with the iac. The tps is centered on the ybro5ttle body. The iac is more on the perimeter. An additional test I do after checking the valve is to plug it back in while it is still off the throttle body and verify that it actuates a little when the key is turned on. It should back up a tad to allow idle air through the passage for starting.TESTINGDisengage the IAC electrical connector.Using an ohmmeter, measure the resistance between IAC terminals A and B. Next measure the resistance between terminals C and D.Verify that the resistance between both sets of IAC terminals is 20-80 ohms. If the resistance is not as specified, the IAC may be faulty.Measure the resistance between IAC terminals B and C. Next measure the resistance between terminals A and D.Verify that the resistance between both sets of IAC terminals is infinite. If the resistance is not infinite, the IAC may be faulty.Also, with a small mirror, inspect IAC air inlet passage and pintle for debris. Clean as necessary, as this can cause IAC malfunction.Fig. Fig. 2: Using an ohmmeter, backprobe terminals of the TPS sensor to check for proper resistancesFig. Fig. 3: The TP sensor and IAC sensor are usually located at the side of the throttle bodyFig. Fig. 4: Idle Air Control (IAC) valve wiring and terminal identificationREMOVAL & INSTALLATIONDisconnect the negative battery cable.Disengage the electrical connection.Remove the IAC valve. On thread-mounted units, use 1 1 / 4 in. (32mm) wrench and on flange-mounted units, remove the screw assemblies.Remove the IAC valve gasket or O-ring and discard it.To install:Clean the old gasket material from the surface of the throttle body assembly on the thread mounted valve. On the flange-mounted valve clean the surface to ensure proper O-ring sealingInstall the valve with a new gasket or O-ring. Tighten the thread mounted assembly 13 ft. lbs. (18 Nm) and tighten the flange mounted attaching screws to 28 inch. lbs. (3 Nm).Engage the electrical connector to the IAC valve.Connect the negative battery cable.
Sounds like the pitman arm. See #5 on diagram below. It has a ball joint with grease that is held in with a boot. It the boot is cracked open, you should replace the arm. You will need an alignment after replacing the arm. The arm does not contain any steering fluid, so if that is leaking, you have another seal broken somewhere...
Most likely the switch has died. They over heat and melt inside and at the plug. Also look at the ignition wires under the dash, Sometimes they can chaff against the column or frame.
I would go get a new distributor because gmc and chevy trucks are known for the gear that runs on the cam to get a little worn out and then the computer doesn't know where to advance or retard the timing to. So try that. I had a similar issue and I tried everything under the hood and it was just what I discribed.
i have heard that the ignition switch can be faulty and not let the full voltage thru to the electricaly controlled 4l60e trans.i have the same problem with my 95 1/2 t. i rigged a switched wire from the fuse block via a relay to the proper wire on the trans....ask a trany tech and they will know what im talking about,,,good luck
There are propriety brand sprays you can get at your parts store that will soften old gaskets. Be careful digging at the surface so as not to score or damage the surface.