My truck started to run rough when first started,once it warmed up it runs fine.Any help would be appreciated
My car has 220000 miles.
My car has an automatic transmission.
Engines require more fuel to start and run properly when cold. If the fuel mixture is either too rich or too lean for cold running, the engine can run rough or even stall. The fuel mixture can be effected by a number of things. If there is a vacuum leak, the engine can be taking in too much air which changes the air/fuel mixture and run rough. A cracked air intake hose or a loose/detached vacuum line can be the cause. Also, improper sensor values can be a cause, even without setting the check engine light. An intermittent fault with the coolant sensor (or any other sensor) for example. The engine control unit relies on the coolant temperature to determine engine temperature. If it is not providing correct readings, the ecu may not determine that is is a cold start and make the fuel mixture richer. If nothing obvious like a vacuum leak is found, have a certified technician look into the cold rough running. With the proper scanner, a technician can observe individual sensor readings and values to determine if any are at fault.
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