Poor idle/shuts off while at idle

Hi,

There are many things that can cause this. I need to know if your truck is fuel injected or has a carburetor.

Here is a list of possible issues:

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1992 Mazda Truck B Series Truck 2WD L4-2184cc 2.2L 2200 MFI
Stalls at Idle, Deceleration
Vehicle Powertrain Management Emission Control Systems Testing and Inspection Symptom Related Diagnostic Procedures Diagnosis By Symptom Stalls at Idle, Deceleration
STALLS AT IDLE, DECELERATION
Engine stalls at stops and on deceleration.

POSSIBLE CAUSE (W/CARBURETOR) ACTION

EGR valve always open,
or gasket leaking Check EGR system.
....................

Ignition timing incorrect Check ignition timing.
See ADJUSTMENT PROCEDURES.
....................

Restricted exhaust system Check catalytic converter.
....................

Idle speed too low Check idle speed.
See ADJUSTMENT PROCEDURES.
....................

Deceleration fuel cut-off valve Refer to FUEL SYSTEMS
....................

Vacuum leaks Inspect vacuum hoses,
intake air ducts, carburetor base
and manifold.
Refer to FUEL SYSTEMS.
....................

Fuel metering problem Check float level,
in carburetor. internal vacuum or fuel leaks,
fuel solenoids (operation),
restricted metering jets, etc.
Refer to FUEL SYSTEMS.
....................

Evaporative system malfunction or leak Check evaporative emission system.
....................

PCV system clogged, restricted or leaking Check PCV system.
....................

POSSIBLE CAUSE (W/FUEL INJECTION) ACTION

Ignition timing incorrect Check ignition timing.
See ADJUSTMENT PROCEDURES.
....................

Restricted exhaust system Check catalytic converter.

....................

Base idle speed too low Check idle speed
See ADJUSTMENT PROCEDURES.
....................

Idle speed control valve defective Refer to COMPUTERIZED
ENGINE CONTROLS
....................

Unmeasured air (vacuum leaks) Inspect air flow meter,
vacuum hoses, intake air ducts
and manifold.
Refer to FUEL SYSTEMS.
....................

Evaporative system malfunction or leak Check evaporative emission system.

....................

PCV system clogged, restricted or leaking Check PCV system.

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Since it runs good other than idle, I suspect you have a vacuum leak. Here is a link that shows how to check for one:

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

It could also be something as simple as just adjusting curb idle speed, but I need to know what system we are working with.

Let me know.

Joe