a few weeks ago my truck started to idle real low when it was cold, about 500 rpm, then it would be normal after a short ride. now its getting worse, it takes quite a while for it to go back to normal idling.

I run biodiesel and had a tankfull of not so great stuff so maybe that it to blame, but the truck is real smooth, even when idleing at 500rpm, it doesnt shake much. when I step down it responds fine and takes off with no problems. There is no definate miss like a bad injector either, unless they are all tired out which is a possability.

I am not sure what to think, just looking for some input. I am going to get a fuel filter after work today and see what that does. let me know if you have any comments.


Thanks

 

My truck will do the same thing when it is cold out on a start. Once it is warmed up it will come back up to about 750 rpm.

 

When I put 12 gallons of straight soy oil in the truck in my sig to top it off mine did the same thing bcause I didn't really drive it much because for four months of being off work it got really cold.

 

I drive the truck every day, and it is in the 70's to 80's most days.

 

There are high idle throttle screw control that you can use or as in my Brother in laws case he used a solenoid and switch, flick the switch and you have preset high idle . the old school one is used in a lot of the older big rig trucks and farm trucks may want to try princess auto or some Ag place