Engine has Erratic Operation

[siml8r5]

Hey there! I'm hoping you can help. I have a 99 Silverado LS 1500 with a 5.3L V8. It has 72k miles and I'm having problems with the engine. In the morning, it starts right up if it's cold. If I get it to Normal Operating Temp and shut it off for a half hour or so, it's harder than hell to start and when it does, I get white smoke out of the tail pipe and a rough idle for 10-20 seconds. Also, when I come to a stop during driving, it runs rough. Like it's mis-firing. Any ideas?

[GM-Tech]

If I had to guess, and I do, I'd say internally leaking fuel pressure regulator. But there's only about 3 or 4 dozen things that could cause what you're experiencing, so without more specific diagnostic information, that's the best I can do.

[MTRMAN5]

Hey there! I'm hoping you can help. I have a 99 Silverado LS 1500 with a 5.3L V8. It has 72k miles and I'm having problems with the engine. In the morning, it starts right up if it's cold. If I get it to Normal Operating Temp and shut it off for a half hour or so, it's harder than hell to start and when it does, I get white smoke out of the tail pipe and a rough idle for 10-20 seconds. Also, when I come to a stop during driving, it runs rough. Like it's mis-firing. Any ideas?

 

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WHITE SMOKE AND ROUGH RUNNING IS AN INDICATION OF ANTI-FREEZE LEAKING INTO THE CYLINDERS, ARE YOU LOSING ANY COOLENT? PULL THE SPARK PLUGS AND CHECK WHICH ONE OR ONES THAT HAVE NO CARBON ON THEM IF IT IS TWO CENTER PLUGS YOU GOT A BLOWN HEAD GASKET. ALL THE PLUGS SHOULD HAVE ABOUT THE SAME COLOR, IF ANY ARE DIFFERENT THAT WILL BE THE CLUE...