I have had idling issues on my 90 chevy k1500 for about 6 months now and i cannot figure out what is the problem. the other day I had just drove for about half hour and when I got home I got out of my truck and I heard the fuel pump priming when the truck was running I have about half a tank of gas left and it idles very low. is it time to replace the fuel pump? Sometimes when I'm sitting at a stop light the truck will idle so low it almost dies and then rev itself back up to normal and repeat. (I recently rebuilt the tbi)