Rough idle

Hi new guy here, i was hoping for some help with my truck. I have a 88 with v6 auto, it has a bad idle ,the tach does not fluctuate, and its this way in any gear ,but once you get on the gas it smoothes out untill you stop and the rough idle is back, it doesnt stall, i looked for a vacum line off but dont see anything wrong. is there a sensor or something that could be causing this? thanks

all i can really think of is maybe there is a vaccum leak that u haven't found or maybe your timing could be out a little?

I would check the EGR vaulve,94 4x4 ranger