GM-GMC: Engine rough start, sequential fuel injection, gmc yukon

Question
QUESTION: I have a 98 GMC Yukon(1500) w a 5.7L Vortec. I have been battling a starting issue. It will start up right away when the engine is cold. It will start rough if you drive it around (so it's warm) and then let it sit anywhere from an hour to half the day. However, if you drive it let it get warm turn it off wait a few second and the crank it she fires right up. Plugs, wires, ignition coil, and ignition control module all have been replaced. (she needed the tune up any way) but they seem the have no effect on the issue. Cap and rotor were replaced a few months ago.

ANSWER: Check the map sensor. Unplug it and see if the issue still exsists. Get back to me once you do this and let me know the outcome.

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QUESTION: Still the same. Rough hesitation then runs normal. I first started it without doing anything just to make sure she did it and it did. Then, I went and disconnected the MAP sensor (its a CSFI Central Sequential Fuel Injection) and it started rough. I waited an hour just to check again and it did the same thing. I shut it off and waited a few seconds and the second crank fired it right over just like it always does. Any other tips.. I appreciate the help by the way.

Answer
sorry it took a while I was out of town and i did not have time to get to this. alright so let me get this straight upon first start up after sitting its rough? then after its warmed up a bit if you shut it off and crank it it is no longer rough?

you changed exactly what when you did the tune up? and this issue was apparent prior too the tune up?

i had this issue on a couple of my vehicles but only after a tune up.