97 GMC Jimmy no start

Yeah, stop throwing parts at the damn thing and do some detective work. First off check for spark and fuel. Use a spark gap on a plug wire to see if there is spark. Use the fuel pump run wire under the hood to power up the pump, is it working? (you should be able to hear the pump whine) Check for fuel pressure. Since it is a 97 plug a scanner into it and see what shows up.

there is spark and fuel just wont fire over. has 4.3 vortec with 140000 miles, so i was told it would be either timing jumped a tooth or crank sensor so i changed both, still does not run.

timing cannot jump since it has chain. Check distributor,

pull one of the spark plugs, and check it out if itis wet with gas., If not put it or crank it without spark plugs to get same gass smell..(donot over crank..)

Check your oil if it is too thin.(it might point out a faulty injector)

if you changed timing chain, i putmy money on wrong timing. Eighter your distributor is 180 degrees wrong, or you missed a toot. Sorry for my previous message(i was just ignorant not to read your message right)