I have a 2001 tahoe 5.3 v8 4wd. Change the oil every 3,000 miles. Never any issues until this past winter. When it is under 50 degrees and the truck has been sitting all night it will jus crank but will not start. If the temp is over 50 degrees then it fires right up. I have replaced recently the MAF sensor, the coolant level sensor in the block and last year replaced the fuel pump.
when it does start will run beautiful all day and always start right up as long as it does NOT get cold.
Local chevrolet dealer can't figure it out, very frustrating...

 

yr gonna have to locate what is missing during the no start.

Check for codes; full function scan tool required and it may be a communication code. What do the temp sensors read...any correlation codes....check all temp sensors....after sitting overnight..they should all read close to thesame temp.


check for spark...if you don't have spark...move back to the power supply to the coil...pcm...and check there.

 

I have NO codes when cranking or with KOEN. gauges appear to be working correctly. Unit has spark and I can hear the fuel pump running. Just won't crank under 50 degrees, which is really weird. at 53 degrees fires right up first crank ant 49 degrees cranks and cranks and cranks..thanks though !

 

can your scan tool read U codes?
check for fuel pressure leakdown with a fuel pressure gauge on the fuel rail Schrader valve.

post the readings from all the temp sensors when the fault is occurring. ie coolant, trans, intake air, ambient temp