My truck is having problems starting in temps 32F or less. It turns over but won't start. Once it does start (if it even does) it runs fine. Here is what I know it is not as I've replaced....

Battery
Fuel Pump
Fuel Filter
Fuel Pressure Regulator
Spark Plugs
Cleaned MAF
Tested Engine Coolant Temp Sensor
Installed Engine Block Heater Plug...no difference


Thoughts????? Even though I cleaned the MAF, I tested the first two prongs for resistance and got nothing......so maybe MAF? I'm not sure what else to try.....

 

Gasoline engine ? Pull a vaccum on the engine and look for an intake leak. I had the same problem you describe here a couple years ago, faulty intake gasket. Once the engine starts the the problem was gone in seconds. Made it very difficult to diagnose.