Q: Car starts weak and rumbles
Hello everyone, I want to thank you in advance for reading over my car troubles. I drive a 2005 ford 500 with about 55,000 miles on it. So today when I cold started my car it started weak, rumbled, and was at low RPMs for about two seconds. After those two seconds, the car quickly went up to about 1,700 RPMs while in idle, and otherwise drove fine. Once I got to my destination I shut off the car and immediately restarted it, and this time the car started up fine. The issue seems to be after I let the car sit a few hours. The weather today was colder than normal and I do have an older battery. If anyone has any ideas or similar issues, I would like to hear from you. Thanks again.
My car has 55000 miles.
My car has a manual transmission.
As a general rule, car engines do not like cold weather and do not do operate as well in cold weather. When you start your car in the morning and turn the key to on, the coolant temperature sensor immediately reads the temperature of the coolant and relays this to the computer indicating that the coolant is cold. The computer then knows at this point that it needs to enrich (add more fuel) the air/fuel mixture at startup due to the change in air density. When you start the car, you will notice that it idles high for a period of time until the engine warms up. This is the enrichment cold start process. This is done with what is called a cold start injector which injects more fuel into the motor until the engine reaches a specific operating temperature. The computer simply feeds a little extra gas through the fuel injectors to start the engine and then maintains a certain amount of fuel supply to the motor until it is warm. I would recommend having an expert from YourMechanic come to your location to take a look at your vehicle and diagnose your cold start issue.
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