I've got a 2000 2wd 3.0 ranger. the other day my ABS light came on and since then every time I hit my brake peddle or turn on my right blinker my speedometer will go up and down all crazy like, and my brakes will stiffen up or give a little. Also my brake pedal will occasionally make a random ticking noise. Also it sounds like when I hit my brakes while I'm idling the engine will slow down. I changed the brake booster out and that didn't fix anything. Has anyone had a problem like this before? anyone got any ideas?

 

I had a 2004 Pontiac GTO, it also had a issue like your with the Speedometer, turning signals and tachometer.

I was told by GM I had to bring it is to reprogram the computer.

What I did instead was purchase a tuner and flashed the computer with a performance tune which cured the problem.

RonD seems to be up to date on these trucks wait for him to respond or others may have more useful information.

If it was my truck I would look for any relevant TSB's to see if any apply to your problem.