After I drive it about 15 minutes it runs smooth. The check engine light does not come on during this time. What could it be?
My car has 165000 miles.
My car has an automatic transmission.
Hello. If the vehicle has a hard time staying running when it is first started then it may have one of several issues. Most of the time this is the result of a leaking fuel injector or a failing fuel pump. If the fuel pressure is dropping off when the vehicle sits over night then it will run like this when it is first started. If the fuel pressure is fine then it may have a bad valve seat which is common on this engine. This causes a compression issue on a single cylinder until the engine warms up and the expansions seals it up. I usually do a cold compression test to verify this. If the compression is fine then I would move on to checking for vacuum leaks as an intake manifold gasket leak is common on this engine and will cause this. If you need to have this stuttering issue checked out further, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose and repair this.
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