having problems with my 94 Yukon 350 tbi. Mornings such as today, lite frost then warm up, she doesnt want to start.Just cranks and cranks, then it wants to fire sputters then eventually starts. Same thing last winter. No codes, no chek engine lite. Was just in for a tune up, mechanic said it was O K.Had to be towed in last winter.Ran fine all summer, just overnite in these conditions.Last place had it hooked up to a Sun machine and sprayed water over everything. Has me and two shops stumped. Any ideas? Thanks, Jim...btw 180,000 miles

Have you checked cold fuel pressure? sounds like fuel pressure bleed off when cold.

Try checking your coolant temp. sensor also ,sometimes will not set a code

I don't know if the Yukon shares the similar fuel injection engineering as my 95 Blazer but I had the same problem that your are describing. I had to replaced my central fuel injector to fix the problem.
My car was hard to start cold but gave no check engine light. This is a common problem with Blazers around 100,000 miles.
Inside the plenum there is a central fuel injector that begins to leek fuel into the plenum. I have seen some Blazers with a plenum full of fuel (5 cups).
Once I replaced the central fuel injector and my problem went away.
You may want to try turning your ignition to the on position (without starting the engine) and letting the pump completely charge the fuel system (you will hear it run for 5 seconds then stop. Turn the ignition off wait two min. Turn the ignition on again and let it charge fully a second time. Then try to start it. If it starts quicker then before then it is probably the injection system.

Central fuel injector for my Blazer = $400 with gaskets.

You may want to check with your local GM dealer as well. They know of these common problems.

Thank You all for the replys