I am new to the forum and have just purchased an '89 F250 with the 460 and 5 speed manual tranny. It is basically a ranch truck, but I am trying to resolve a few issues with it. I set the cruise, and it worked fine for a few miles. All of the sudden, the truck started to sputter and I thought it was going to die. All of the sudden, the engine started revving. I put it in neutral, and the thing just started redlining. I tapped the brake, and it quit, then ran fine the rest of the way home. any thoughts?

 

Three ways to ways to cancel automatic speed control.

Press brake pedal or clutch pedal.
This cancels the automatic control until you press
the Set Accel or Resume switch.

Press the Off switch.

Caution: Do not shift to neutral when using speed control.
This will cause the engine to over rev.

 

The cruise is why it redlined. The cruise control works like this.
You're moving 60mph, you set the cruise. There are a series of pulses that the control box receives from the speed sensor. The control box opens a vacuum solenoid and passes vacuum to a vacuum motor that operates the throttle. As your speed decreases the pull on the throttle increases to raise the RPM of the engine. If you place the transmission into neutral there is no load on the engine and it will red line.

It sounds like you have a vacuum leak in the cruise control system. That's were I'd start.

 

doesnt the tin can looking thing have something to do with vaccum and cruise control

 

The 'tin can looking thing' is a vacuum reservoir and is more for the heater controls than the cruise control. There should be a separate one for the cruise control.

 

thnx i got my truck from my grandpa and he was know to rig things so for a few minutes i actually thought he rigged something with a soup can till i popped the hood on the other truck on found a similar one there to