When driven on the highway at 60mph it acts like it want to shut off..now it won't start..I put in New spark plugs and it still won't start...and I need to replace the muffler...what else could be the problem of the diagnostic code read a 708...please help

I have replaced the starter and relay switch and also a new battery and it still will not start. Makes a clicking noise when trying to crank , what else could be the problem?

Somebody on repair pal when commenting on my problems said that I had two blend doors told me how to diagnose the problem by turning the ignition on without turning the engine on and listening for a humming noise. He diagnosed it right I do hear the humming noise, the blend or over the heater core is opening, but where in the hell is the second blend door or the actuator that runs it. I called around to some parts houses and they do not know what I'm talking about. Help.

This thing looks kind of like a shock absorber with a handle on it. The person that owned it before me did have a lot of extras added on as far as heavy duty suspension. But I cannot figure what this thing is under the seat, and yes it is attached to the truck.

seems fuse somewhere may be blown but not inside cab. is there another place I need to look

Overheated and not a drop of water in tank. Also it's smelled like antifreeze for about 2 weeks, doing know if that has anything to do with it though

I have replaced the master cylinder three times , the brake booster rear wheel cylinders ,shoes and front pads bleed brake each time .

when I try to move the seat it may move very little . the other buttons move the seat up& down

Doesn't seem to do this when I'm running around town, only when I'm on the highway.