2000 cougar brake problems

I have a 2000 cougar V6 automatic and installed front pads on her in March of 03. Ever since then, when I'm driving at high speeds 40-75mph, if i have to hit the brakes the brake pedal pulsates and you can feel grinding like the anti brakes are activated. Today, i pulled the pads for inspection and they look fine with pretty much even wear.
When i purchased the pads, they listed two types of pads. Ones with sensors and non sensors. I purchased the non sensor pads because that what seemed to come off the car.
Can anyone help??
The brakes were fine before i did the brakes

sounds like the nonsensor pads are for non abs cars and since you do have abs the system freaks out since you have the incorect pads so i guess the best it would be to buy some sensor pads

btw this is just an educated guess

No, the pads didn't have any wires attached to the back of them. Yesterday i went to advance auto and looked at the senor pads, they have holes in them for the sensors.
Last night we went to BJ's to get new tires and what i did just find out, my wife, girlfriend at the time of the brake job, had a rear tire blow out and she replaced the tire w/215-55-16 in which there were 215-50-16's on there. Last night i replaced the other three tires because they were pretty much wore down to the indicators and the car is due for it's inspection. :naughty: ta da, that took care of the problem. Remarkable, i wouldn't think being off 50 - 55 on the width with the tire on the rear left would effect the anti lock brakes on the front.

Thanks,
brakes work excellent now.

:banghead: