What is the reason for the Buick Regal 2.5 stalling during cold starts?

[LeEsther]

The reason for the Buick Regal 2.5 stalling during cold starts is excessive carbon buildup in the throttle body or leaks in the intake manifold or various valves. There are three key points for engine maintenance: Clean the air filter: The air filter is related to the engine's air intake during driving. If the air filter is clogged or accumulates too much dust, it will cause poor engine air intake. Additionally, a large amount of dust entering the cylinders will accelerate carbon buildup, leading to poor engine ignition, insufficient power, and naturally increased fuel consumption. Remove throttle body sludge: Sludge is formed due to carbon deposits from fuel combustion exhaust at the throttle body, as well as impurities not filtered by the air filter accumulating there. Excessive sludge can cause air resistance in the intake, leading to increased fuel consumption. Clean injector carbon deposits: Since the combustion chamber is prone to carbon buildup, which can cause difficulty starting, carbon deposits on the injectors can also clog fuel passages, distort fuel injection, and result in poor atomization, naturally increasing fuel consumption.

[IslaAnn]

As a car enthusiast, I believe the reasons for cold start stalling may involve the fuel and ignition systems. For the Buick Regal 2.5 with its V6 engine, during a cold start, the engine requires additional fuel concentration to ensure smooth ignition. If the fuel filter is clogged or the fuel injectors have severe carbon buildup, it can lead to insufficient fuel supply. Similarly, worn spark plugs with excessive gap or faulty ignition coils can cause unstable ignition, both of which are prone to causing stalling in cold weather. I recommend first checking these basic components, cleaning the fuel injectors or replacing the spark plugs if necessary. Regularly changing the engine oil can also reduce carbon buildup and maintain stable starts. Additionally, a dirty throttle body may obstruct airflow, so it's advisable to have a professional mechanic check the sensor data. In short, older cars require diligent maintenance.

[MacMargaret]

I've driven quite a few older cars, including this Buick Regal 2.5. It often stalls during cold starts due to temperature sensor or intake issues. For example, a faulty coolant temperature sensor sends incorrect signals to the ECU, causing the air-fuel mixture to be too lean or too rich; a dirty mass airflow sensor can also lead to insufficient air supply, making it difficult for the engine to maintain idle after starting. Cleaning the throttle body or replacing worn parts usually solves the problem. A friend of mine had a similar issue, which turned out to be low fuel pump pressure—stepping on the gas stabilized it. For prevention, regularly check the air filter and sensors, and use high-quality gasoline to reduce impurities. With proper maintenance, older cars can still be reliable.

[McKaleb]

From the perspective of the engine management system, the cold start stalling issue in the old Regal 2.5 may be related to idle control system failure. The ECU relies on sensors to adjust the air-fuel ratio. When the coolant temperature sensor malfunctions or the idle air control valve gets clogged, insufficient air intake after startup directly causes stalling. I've also seen ignition system aging leading to backfire issues. Check whether voltage and circuit connections are normal, especially since older vehicles are prone to oxidation problems. Maintenance is key - timely cleaning can extend service life.