Periodically my trucks brakes will pulse on and off like the ABS is messed up and then seems like the brakes are engaged when I have my foot off the peddle. Feels like it’s definitely all 4 wheels doing it so I wouldn’t think it would be a caliper problem. Any ideas?

 

A quality, capable scan tool should provide the info if any wheel speed sensors are involved. The graphing function narrows it down quite well.
It doesn't have to be a sensor problem, it could be a wiring or connection problem
Also if there is a brake hose with a partial restriction the fluid cannot return to the master completely and this can make it feel like the brake(s) are not fully releasing. What sometimes helps is to feel the wheels after a short drive, if you feel one wheel is much warmer than the rest, that is the wheel with a problem.

 

Everything that you said has run through my head it’s just that I don’t have a scan tool readily available. Appreciate the response! I was just thinking that if it was a wheel sensor or an abs problem a check engine light would come on. It could very well be a collapsing line though. You think water in the brake fluid would cause this problem? I’ll try and get a scan tool and run some test. Thanks and appreciate the help