Truck stalls out in gear

Good evening,

Yes, it could be a vacuum leak but I doubt ti.

It could be the idle air control valve or the throttle body being dirty. I attached some guides for you on the issue.

https://www.2carpros.com/articles/stall-at-idle

https://www.2carpros.com/articles/how-to-replace-an-idle-speed-control-motor-iac

Also, a stuck open EGR valve will do this as well.

As far as the hard starting, it could be a bad fuel pump but needs to be checked.

https://www.2carpros.com/articles/engine-cranks-excessively-before-starting

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Roy

Yes, it would.

Can you 2 foot it and keep it running?

Roy

NOTE: The IAC valve is an electrical component and must not be soaked in any liquid cleaner or solvent. Otherwise damage could result.

IMPORTANT: Thread-mounted IAC Valves have a dual taper, 10 mm diameter, pintle. The flange-mounted IAC valve and has a 12 mm diameter, dual taper pintle.

Any replacement of an IAC valve must have the correct part number, with the appropriate pintle taper and diameter for proper seating of the valve in the throttle body.

REMOVE OR DISCONNECT
1. Electrical connector.
2. IAC valve.
On thread-mounted units, use a 32 mm (1-1/4") wrench.
On flange-mounted units, remove screw assemblies.
3. IAC valve gasket or 0-ring and discard.

CLEAN
Thread-mounted valve - Old gasket material from surface of throttle body assembly to insure proper seal of new gasket.
Flange-mounted valve - IAC valve surface on throttle body to assure proper seal of new 0-ring and contact of IAC valve flange.

NOTE: If the IAC valve was removed during service, its operation may be tested electrically with the IAC system analyzer (J 37027 or BT- 8256K). However, if the valve pintle is extended electrically, it must also be retracted electrically. Before installing an IAC valve, measure the distance between the tip of the valve pintle and the mounting surface. If the dimension is greater than 28 mm (1.10"), it must be reduced to prevent damage to the valve. This may be done electrically using on IAC system analyzer motor tester (J 37027 or BT-8256K).

MEASURE
Distance between tip of IAC valve pintle and mounting flange.
If greater than 28 mm, use finger pressure to slowly retract the pintle. The force required to retract the pintle of a new valve will not cause damage to the valve.

IMPORTANT: No physical adjustment of the IAC valve assembly is required after installation. The IAC valve pintle is reset by the control module system which causes the valve pintle to seat in the throttle body. The control module then has a reset procedure to set the correct pintle position. Proper idle regulation should result.

INSTALL OR CONNECT
1. IAC valve into throttle body as follows:
Thread-mounted valve - Install with new gasket.
Flange-mounted valve - Install with new lubricated 0-ring, using attaching screw assemblies. Tighten Thread-mounted IAC valve assembly to 18.0 Nm (13.0 lb. Ft.) With 32 mm (1-1/4") wrench. Tighten Flange-mounted attaching screw assemblies to 3.2 Nm (28.0 lb. In.).

2. Electrical connector to IAC valve.
3. Reset IAC valve pintle position:
Remove battery cable for 10 seconds.
Ignition "ON, " engine "OFF" for 5 seconds.
Ignition "OFF, " for 10 seconds.

Then I would suspect the IAC. I would also clean the throttle body as well to make sure all the carbon build-up is off the plate.

https://www.2carpros.com/articles/throttle-actuator-service

Roy