rapid misfire

2006 BUICK LUCERNE
130 MILES • 3.8L • 6 CYL • 2WD • AUTOMATIC
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The car will not start when the motor is cold sometimes it will start in the morning when it does it is a rapid misfire until the engine warms up and then runs perfect all day long, as long as the engine is warm it starts and runs fine then when it sits overnight then same thing in the morning rapid misfire
Oct 16, 2019 at 3:35 PM
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JACOBANDNICKOLAS
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Welcome to 2CarPros.

Since it happens on a cold start, there are a few things that may be causing it. First, the engine coolant temperature sensor may not be working properly causing a fuel mixture issue when cold. Or, there could be a low fuel pressure issue when it first starts.

I want you to try a very simple test. This will help eliminate a possible low fuel pressure issue.

1) From the off position, turn the ignition switch to the run position (engine off) and count to 5 and turn it off.

2) Repeat step 1 three times and on the 4th, see if the engine starts and runs properly.

Do this when it is cold so I know what to tell you. Let me know the results.

Joe
Oct 17, 2019 at 7:48 PM