Rest base idle - 1987 Chevrolet S-10 Pickup

The motor and carriage is all one part and must be purchased as a unit, contact a local dealer for this, very expensive.

You can't adjust the idle , There is a minimum idle adjustment set at the factory , you don't want to mess with that . The PCM / ECM ,engine computer controls the idle speed by the idle air control valve (motor) . You may have a dirty throttle plate mess with the base idle .Check out this video on ford base idle adjustment . Some one who didn't know cranked up the base idle causing problems Ford IAC valve test how to adjust minimum idle speed

Have you checked base fuel pressure with a gauge yet ?
Sounds like the pump is weak.

It should have a base idle adjustment and could also have an idle speed control motor.
The base idle screw should be on the driver's side of the carb. You would also have a fast idle screw on the choke.

Is there a vacuum hose off or leaking somewhere? Maybe a throttle body base gasket?

Unfortunately, this is a problem with a thing called the idle step control (I.S.C.) motor. To prevent having chokes like we used to in the old days, the engine automatically adjusts the idle depending on engine temperature/load conditions. The I S C motor is the component that does this.

Sometimes if the battery dies or if there is a lto of carbon nbuildup (from unburnt fuel), this isc motor goes out of alignement....you will have to take it to a mechainc where they will be able to rest the base idle settings and this adjustment as well.

there is no carb, and no adjustment. if it idles too high, there is a vacuum leak, so check the large hose going from the base of the throttle body to the valve cover. if thats OK, these are known to have a leak at the base gasket, usually at the rear of the throttle body. spray carb cleaner around the base and see if the idle changes, if it does, replace the base gasket.

Idle Speed Control (ISC) Motor OPERATION Eagle Throttle Body Fuel Injection (TBI) System NOTE: The Eagle TBI system is used only on 2.5L Premier engines. The Idle Speed Control (ISC) motor is mounted to the throttle body and controlled by the PCM. The throttle lever rests against the initial adjustment screw of the actuator (plunger). The idle speed is not adjustable. The initial adjustment screw is only used to establish the initial positioning of the actuator when the ISC motor has been replaced. The actuator extends or retracts to control engine idle speed and to set throttle stop angle during deceleration. Based on inputs from the various engine control system sensors and switches to the PCM supplies current to the ISC motor to adjust the actuator position for the particular operating conditions.
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1. Inspect the 2 wire harness for the 7x Crankshaft Position (CKP) sensor in the rear of the block.

2. Wiggle tug test the harness and inspect the harness for being melted from the exhaust manifold. Tests/Procedures: 1. Verify fuel pressure climbs to over 40 PSI during cranking and reads about 35-40 PSI at idle. Potential Causes: Insufficient Fuel Pressure
Tech Tips: The Powertrain Control Module (PCM) will idle the engine at a normal speed when the Throttle Position Sensor (TPS) voltage returns to the learned base idle value. This is also called 0% throttle angle. If this throttle angle is 1% or more at idle, the PCM will assume the engine is actually off idle and raise the engine speed to prevent a deceleration stall. Note that another sensor using the same 5 volt reference as the TPS can momentarily glitch the reference voltage low. This will cause the TPS to send a lower base idle voltage to the PCM, which the PCM quickly records as the new learned base idle voltage. When the reference voltage returns to 5 volts, the base TPS signal voltage increases to it's previous value. The PCM now interprets this as being off idle. This will cause the throttle angle to increase to 1% (or more) and idle the engine at a fast speed

Hansandfranz is 1/2 correct; the car does need an "Idle Relearn", but, you do NOT need a scan tool for this. The vehicle just needs to be driven for the ECu to relearn the "base idle".
Get in, drive it down the highway. Do some passing gear downshifts. Pull off to the side of the road, let it idle for 30 seconds, repeat 2 more times. Then, try to duplicate some "in-town" (stop & go") driving, for about 15 minutes.
This will reset the "base idle", and your stalling condition will disappear. Expect to have to do this again if you replace the battery. Very common; the Computer (ECU) loses the base idle parameters when the battery is disconnected. Easily rectified just by driving as mentioned above. Feel free to comment back if you have any other questions.