dj960

I have a 95 4.3 that was running great. One day went out to start it and it wasn't running good sounded as if it were missing at low rpm. The next day problems got worse, to start it peddal must be held to the floor and key turned for about 30 seconds, once started pedal still on floor it takes another 30 seconds to reach 3000 rpms once there it takes off. let off throttle and the whole process starts over if it doesn't stall. The only thing done between the running good and now was the intsallation of a new powersterring pully and a new belt. It seems like a very rich fuel mix coming out of the exhaust. In a seperate issue my 4x4 started making very loud clicking sounds/jerking when engaged, could this be a seleniod problem?