My engine will not idle?

Good afternoon.

This sounds like you have a vacuum leak, dirty throttle bore or the IAC motor is not working but to be sure lets check out these guides to help us fix it.

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

and

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

and

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

if okay the first thing I would do is check the actual fuel pressure. Low fuel pressure will cause all these codes.

You can rent a tester at a parts store. There is a test port on the supply line back by the distributor. The tester just goes on that fitting for the test.

Roy

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

Okay, good find.

Glad you got it fixed.

Roy

HI Gerald,

Based on what I read here it could be a couple of things.

First it could be the Idle Air Control valve is not working properly. (See link below)
https://www.2carpros.com/articles/idle-air-control-valve-service

Or it could be a large vacuum leak (See link below)
https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Just note that if it is a vacuum leak it would have to be significantly large, something the size of the PCV valve line.

Regards
Jon

Hello,

I would start with a tune up but let's check the battery and the connections which can cause the issue you are describing. Here are two guides that should help us get started:

https://www.2carpros.com/articles/how-to-tune-up-a-car-engine

(use OEM parts)

and

https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked

with

https://www.2carpros.com/articles/car-battery-load-test

Please run down these guides and report back.

Cheers, Ken

This can be the result of a few things. An engine vacuum leak, dirty throttle body, or even the idle air control valve.

What I suggest is to first confirm there are no engine vacuum leaks. Here is a link showing how that is done:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Next, consider cleaning the throttle body / throttle plate. Here is a link showing how that is done:

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

If that still doesn't help, then I suspect it is related to the idle air control calve (IAC). The IAC is responsible for maintaining idle speed. Take a look through this link. It shows in general how one is serviced and the second shows general replacement.

https://www.2carpros.com/articles/idle-air-control-valve-service

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

__________________

Here are directions specific to your vehicle for replacement. The attached pics correlate with the directions.

________________

2002 Chevy Truck S10/T10 Blazer 4WD V6-4.3L VIN W
Procedures
Vehicle Powertrain Management Fuel Delivery and Air Induction Idle Speed/Throttle Actuator - Electronic Service and Repair Procedures
PROCEDURES
IDLE AIR CONTROL (IAC) VALVE REPLACEMENT

REMOVAL PROCEDURE

pic 1

1. Turn OFF the ignition.
2. Remove the air cleaner outlet resonator.
3. Disconnect the idle air control (IAC) valve harness connector.

pic 2

4. Remove the IAC valve mounting screws.

pic 3

5. Remove the IAC valve and O-ring from the throttle body assembly.

CLEANING AND INSPECTION PROCEDURE
1. Clean the IAC valve O-ring sealing surface, pintle valve seat, and air passage.
Remove excess carbon deposits with a small amount of carburetor cleaner on a parts cleaning brush. Follow any instructions on the cleaner container regarding cleaner usage.
DO NOT use a cleaner containing an extremely powerful solvent such as methl ethyl ketone.
Shiny spots on the pintle and seat do not represent a bent or misaligned pintle shaft.
If heavy deposits are present in the air passage, remove the throttle body for a complete cleaning.

IMPORTANT: DO NOT reuse the original O-ring.

2. Replace the IAC valve O-ring.

INSTALLATION PROCEDURE

IMPORTANT: Use an identical pan when installing a new idle air control (IAC) valve. The IAC valve pintle shape and dimensions are designed for specific applications.

pic 4

1. On a new IAC valve, measure the distance between the IAC valve pintle and mounting flange. Use finger pressure to slowly retract the pintle if the distance is more than 28 mm (1 - 1/8 in).

pic 5

2. Lubricate the IAC valve O-ring with clean engine oil.
3. Align the flange holes with the mounting holes on the throttle body assembly.
4. Insert the IAC valve through the O-ring into the throttle body assembly.

NOTE: Refer to Fastener Notice in Service Precautions.

IMPORTANT: The screws used to attach the IAC valve are coated with thread locking adhesive. Clean the attaching screw threads and apply thread locking material GM P/N 1052624 or equivalent.

pic 6

5. Install the IAC valve mounting screws.

Tighten
Tighten the screws to 3 N.m (27 lb in).

pic 7
6. Connect the IAC valve harness connector.

pic 8

7. Install the air cleaner outlet resonator.
8. Perform the IAC Reset procedure:
8.1. Turn ON the ignition, with the engine OFF, for 5 seconds.
8.2. Turn OFF the ignition for 10 seconds.
8.3. Start the engine and check for proper idle speed.

Let me know if this helps or if you have other questions.

Take care,
Joe

Has the check engine light come on? Also, when was the last tune up?

When you say it doesnt move right away, does the engine rev up like the trans is slipping? When it dies, does it sputter out like it has run out of gas or does it just shut down?

Start by having the PCM scanned for trouble codes

I feel that you have unplugged the main transmission harness, from what you describe I feel that the TTC lock up solenoid has failed, I suggest that you get a diagnostic scan done to confirm this, start here.

That sounds like a bad vacuum booster unit. When the pedal goes down is it much harder than it used to be? If so check the large line to the booster and the check valve as well. If they are OK Disconnect the hose and plug it. Now test drive it. If the stalling has gone away and you don't hear the hissing the booster is bad. Not hard to change out if you're mechanically inclined.