i dont quite know how to explain it so i'll just explain as i best as i can think of

i left my gfs place this morning to drive home, she lives in wilmington its a 2 hours drive. so i went to leave and the truck is feeling very sluggish. The best description i could think of was that the back right tire was filled with concrete (or maybe something even heavier). it wasn't really making any noises just being very sluggish. so i limp it home barely going the speed limit, and of course its down shifting at the smallest hills and runninghigher rpms than usual.. but just over halfway home it just completely stops running funny and i make it home just fine. This was without stopping once or changing speeds or anything.

Then probably a couple hours later i hop in the truck to run to the store for something, and it is running fine still. But when i get in the truck to leave (was only in the store for 15 mins. or so) the same problem starts up again and progressively gets worse on my ride home.. which is only like 5 minutes.. it got so bad where it was to the point where i would let off the gas and i would kinda be jerked forward like i slammed on the brakes. and i barely made it home.. then just a minute ago i tried it again and i rode around for a while, stopped to get gas and then it did it again when i was heading home.. got progressively worse. but both the second times it "felt" like it was coming from the front left side. and even the first trip to the store when i got home there was smoke or steam coming from the rotor when i stopped, and it smelled real bad.

but on friday i did have my mechanic work on it.. he changed the spark plugs and wires (dont think that has anything to do with it) but he also put in a new master cylinder and changed the brake fluid for me. but at the same time it didn't start acting up til i drove it to the gf's place, which to remind you is 120 miles, drove it quite a bit on saturday, drove a little bit on sunday, and then came home monday (today)

does anyone have any ideas as to what it could be.. and i've had my abs light on for a quite a while but haven't really experienced any problems

 

brakes are engaging while i'm driving.. anyone have any input?

 

Sounds like a siezed caliper. Which could be the reason why it get's better on the highway and gets worse in the city.