not to long i trade my dad's 1990 cadillac sedan deville 4.5 liter for my jimmy.... i was excited cause come on its a caddy.... he has had it for a couple of years and sometime ago he started to put the wrong fuel in it... ragurlar when it calls for premium.... i dont know if thats what causes the problems i have but when i drive from a stop postion it hesitates and drives rough... as if not gettin the gas... i have to slowly depress the pedal and if i dont it jerks all over the road as if i was playin footsies with the pedal.... the shop he took it to told him the distributor but no luck with the problem stopping.... since then he had replaced the fuel filter, pump, coil, plugs and wires, and the distributor.... the check engine light comes on after a while and only then does it start to run better... not factory but better then sputtering down the road...... and occasionally when started either early morning or after work it will idle rough only for a while and then normal idle, but i can hear a kind of draining/ sucking sound coming from the rear of the car... i think its the fuel pump cause he replaced it him self and now it wont read the amount of gas in the tank..... since ive had it i have put nothing but the best gas in it and i has improve since he has drove it last...... please if anyone with info knows something i would love input... it seems like this problem might happen a lot.... thanks!!!!!!!!!!!!!!!!!!!!!!!