Well I think it was about 15 deg. this morning and the 4.8L barely started. The initial start up was fine. It starts on the first turn and I guess the engine senses its very cold and it will bump up the RPMs to about 1500 for 5 or so seconds. Then it will try and drop down to 500, but it basically just starts "grunting" and it will die. It sounds really really bad. What is going on here? Stock 4.8L, 103,000 miles.

Thanks!

 

What kind of plugs do you have? I have NGK Tr6's gapped at about 28 and the first time I go to start it it stumbles a bit and dies and the next time it'll fire right off.

 

Is it totally stock? I'm asking because a lot of people have done the TB Bypass and I've heard it doesn't mix well with low temperatures..

 

bone bone stock. It's never done this before, we have had much colder temps than this. It stumbles only way to save it is by taking it up to 2000 rpm for a while..

 

what oil are you running?

 

You could try cleaning the throttle body and IAC (Idle Air Control) valve as a starting point.

 

mine did the same, i put an optima battery and the increase in crankin amps helped and i can turn my key for a split second and it starts right up, but id do the above also!

 

The truck will idle or run higher rpm when warming up in extreme cold. You will also hear some things opeining and closing, I think its the heat actuated valve that help heat up trans fluid through that section of the radiator.
Kind of strange your having these issues now, 15 dgrees is cold but should be alright for the truck. Have you done or changed anything recently that could account for the way its acting up?

 

I will try the above about cleaning the TB and IAC. Also, I don't know for sure if it was 15 degrees. It may have been collder. Everything was frozen, I couldn't get my windows to open and no winshield wiper fluid would come out.

 

Also, I have forgot to mention, my tranny has also been acted up in this very low temps. You know how normal if you get on the gas pretty light, you will be in 4th gear by about 35mph? Well now, the truck just refuses to shift out of 2nd (or even 3rd gear on the highway). You really have to stab the throttle to get it to shift. But, it works just fine when I drive it home in the eveening.