Surging Idle when braking (1 Viewer)

[Woodini]

Title pretty much says it all, truck is 89 22RE. Thanks for any input.
Ray

 

[gnob]

idle is too high or your tps is not set properly.

 

[bkg]

Vacuum leak?

 

[aztoyman]

What @gnob and @bkg said. If it only happens when you step on the brakes it could be a vacuum leak at the brake booster or the hose to the booster. Good luck and please follow up with your fix. Dead end threads suck.

 

[Woodini]

I also have a pretty sever misfiring, the truck seems to run on 3 cylinders. It can shake pretty bad. Last night I struggled to make it up a 65ft bridge from a light at the bottom.
Could the misfiring be connected to the other issue?

 

[gnob]

idk why this actually needs to be said, but, you simply should not be driving a fuel injected vehicle if it's misfiring.
you need to figure out the misfire and go from there.
compression check to start.