Silverado Engine Stops When Warm

Question :
Hi !! I have a Silverado 5.7 1992 4×4 z1500 and generally on neutral cold or warmed up on low or high rpm’s it works as silk !! When I go drive or reverse ONLY WHEN ITS WARMED UP ( normal temperature) and ONLY ON LOW rpm’s it stops suddenly ( engine gets switched off ) It didn’t sound at all as gasoline circulation problem it’s just stop every time on low rpm’s but only when the engine is normally warm!!! What issue this could be please ?? Your help could be precious because I work with this truck and I have it here in Greece and it’s difficult to find a mechanic for Chevrolet cars or any American car !!! Thank you very much!!!!

Answer:
Based on the symptoms you described, it sounds like your Silverado may be experiencing a problem related to engine stalling under specific conditions of a warm engine. While this may be difficult to diagnose the exact issue without physically inspecting the truck, there are several potential causes to consider below:

Idle Air Control Valve (IAC): The idle air control valve regulates the idle airflow into the engine while the vehicle is idling. If the IAC is faulty or dirty with carbon, it may not properly adjust the airflow when the engine is warm, leading to stalling at low RPMs. Cleaning or replacing the IACV could resolve the problem with your Silverado.

Throttle Position Sensor (TPS): The throttle position sensor monitors the position of the throttle valve and sends signals to the powertrain control module (PCM) to adjust fuel injection and ignition timing. A malfunctioning TPS may cause erratic engine behavior, including stalling at low RPMs when warm.

Vacuum Leaks: Vacuum leaks can disrupt the air-to-fuel ratio and affect engine performance, especially at idle. Check for loose or cracked vacuum hoses, intake manifold gaskets are a common probblem on the Silverado 5.7L engine, or other components that could be allowing air to enter the engine without passing through the throttle body.

Fuel Delivery Issues: While you mentioned that it doesn't sound like a gasoline circulation problem, it's still worth checking the fuel system components, such as the fuel pump pressure, fuel filter, and fuel injectors. A clogged fuel filter or weak fuel pump could result in inadequate fuel delivery, leading to stalling.

Ignition System: Faulty ignition components, such as spark plugs, ignition coils, or the ignition control module, can cause intermittent stalling, particularly when the engine is warm. Inspect and replace any worn or malfunctioning ignition parts as needed.

Engine Sensors: Various engine sensors, such as the coolant temperature sensor or oxygen sensor, play crucial roles in engine performance. If any of these sensors are sending incorrect signals to the ECU, it could lead to stalling issues. A scan on computer codes would be needed.

Since the problem occurs only when the engine is warm and at low RPMs, it may be challenging to replicate the issue during diagnostic testing. Checking and addressing each potential cause should help narrow down the source of the problem. If you're unable to find a mechanic familiar with Chevrolet vehicles in your area, you may need to rely on online resources, forums, or diagnostic tools to troubleshoot and resolve the issue yourself.