Q: Fuel system issues - blue smoke this morning, check engine light on & off, engine vibration

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A few weeks ago, I had to have my car towed in because it wouldn't start & there was a strong gas smell. The garage said the fuel line had come undone, but they couldn't figure out why; only guess was "soft motor mounts." After I got it back, I noticed the engine vibrating/shaking when I start it, then it evens out after the car warms up. Had some start-up issues; got a new battery, but still has some starting issues especially in early, cold morning.The check engine light started flashing on startup, along w/engine shaking, then the shaking would subside & the light may stay on or may go off. This morning, it gave one quick turn-over (1 second), acted like it didn't want to start, then started up and ran ok, though vibrating some & with blue smoke - a lot at first, then subsided some except when accelerating. Never had any of this prior to fuel line coming undone. I'm wondering if there's a fuel line/filter issue? Puzzled, because the car's run smoothly prior to this.

My car has 103000 miles.
My car has an automatic transmission.

Hello. Thank you for writing in. It sounds like you may be dealing with more than one issue. The first thing we should discuss is the blue smoke coming from the exhaust. This typically means that the engine is burning oil. Burning oil can be caused by worn piston rings, worn valve seals, PCV malfunction, engine oil seals, and bad head gaskets. This would cause the engine to run poorly, misfire, shake, and would also soil the spark plugs causing another set of issues. You should look into finding the cause of the oil leak, and fixing that first. Keep in mind the vehicle needs more fuel when it is cold and that may be why you smell fuel when starting. Its because the engine is running very "rich" until it warms up. This may also be playing a factor. Start by tracing down the oil leak, and making the appropriate repairs.

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