1987 S10 problem...help??

[jutland]

so i have been registred on here for a long time but havent posted....so my 87 S10 is haveing some problems it started out that verytime i would go up a steep hill once i got to the top and started braking the check gages light will come one..i lose power brakesand have to use all my wieght to stop it...and it over feuls it runs really rough and wants to die and if i dont keep it at about 3500 rpm it will glug and chug till it dies...well i would park it and let it cool off for a few hours and it would start up and run just fine like my little faithful truck always has...well i was going up a ahill last week that it had made it up the day before with no problems and when i got to the top it started its little fit thing...so i parked it at a gas station and had a friend come pick me up and left it...me and my mom went back about 4 hours later and it still wouldnt run right..was still doing all the same things...so we left it and i came back the next day and it still wouldnt run right...so i ended up having to have my truck towed back to my house...luckily my best friend has AAA lol...so we have replaced that spark plugs...my mom thought it wasnt getting enough spark to burn the feul...it needed it but didnt solve it...so now my mom and grandpa think it is the map sensor...but the check engine light isnt come on...which if it was a bad sensor it would make the check engine light come one...my dad thinks it could be a clogged feul filter which would make sense..i would still get plenty of feul but no pressure or anything...my dad is coming tonight with a sensor and we are gonna hook up my truck and pray that something comes up...so in the meantime if you guys could give me any suggestion as to what you think it could be i would appreciatte it alot...thanks

DM

[jutland]

oh i forgot...dont know how lol...it is a 2.8 liter V6, throttle body feul injected, 5 speed