I have 2005 1500 5.7 and now that the temperatures are getting colder My truck is doing the same thing it was doing last year. After sitting over night I go to start it and its as if its firing on one cylinder and tries to start. It sputters while cranking, pressing the gas pedal while cranking makes it sputter a little more and after cranking it a few times more it starts and idles perfect. I can then shut the truck off and it will start back up just fine. The problem only happens when it sits over night. I can let it sit at work all day and it starts fine at the end of the day. As the temperatures get colder the problem gets worse and worse. Battery is new and it cranks fine. plugs and wires are 4 years old. Like I said before this happened last winter and at the coldest part of the winter it was almost impossible to start, but all summer it was fine. Help.

 

For the first start of the morning, try turning the key On, but, NOT starting the motor..... and listen for the fuel pump to prime. Prime the pump at least twice, (three times would be better) and THEN try and start the truck. Any better?

 

It was 17 degrees this morning. I primed the fuel pump 3 times and it made no difference. Seems like it sparks every eighth time. Had to crank it for a while. When it did start it ran smooth.

 

Hhhmmmm...... Once it starts, does it run ok? Power where it should be??

 

It runs surprisingly smooth after it starts. power is fine. I tried changing the iat sensor with no luck. Could this problem have anything to do with a remote start that was installed years ago?

 

Maybe...... why it would only be a problem cold though..... No idea.

Do you have a scanner available that can read data? Would be interesting to see what the PCM thinks is going on when the engine is stone cold.

 

I do have a scan tool and I get no codes. Not sure which sensor to look at when cold. The problem goes away as soon as it starts so I was looking at stuff with the key on engine not running. Didn't notice anything out of the norm

 

Look and see what the PCM thinks engine temp is when cold. (you can do that with the engine not running.) Also throttle position values, and then see what they look like once the engine starts.....

 

The engine temp before starting was the same as the outside temperature or close to it. The throttle position said 17.2% before I started and after it started it said 15.1 percent and after it's warmed up it said 13.1% . Pressing the throttle does not change the percentage with key on engine off.
do you think I could be a crank position sensor? Where is the sensor on these trucks

 

Ok, that all seems reasonable. I guess the next test would be, are you getting spark, or, at least, signal to fire the coils when cold.