Okay, I'm on my last straw (I think I'm going to run out soon). My truck has this problem where if I let go of the gas after it has shifted to second the rpm's drop down and sometimes it dies. Oh, and only when it's fully warmed. It's died on me in stop and go traffic and in the parking lot. It's a stock 87/350 TBI. I've replaced the oxygen sensor, fuel filter, pcv valve, and spark plugs to no avail. I just got it from the mechanic and they couldn't duplicate it and neither could I. It's been a week since I've changed anything and I had it doing it just yesterday and I know it will do it again, as it has for the past 4,000 miles. The only thing I can think that has changed is that I got the wax pellet that drives the valve to the outside air in the air cleaner working. But I don't think that would cause it to die. There are more things that I could change(egr, map sensor, tps) but they are all starting to get into the $50 price range and I don't want to do that unless I know for sure they're not working. I haven't worried about it too much because I just start it up again and it goes and if it doesn't, I'll find a phone. But tomorrow I'm driving from Boulder to Steamboat and the last thing I need is it dying at 11,000 ft in stop and go traffic at the eisenhower tunnel. Sorry for the long post, any help is appreciated.