I have a '03 Ls 2 door 2 wd blazer that has lately been dies on me. You can start it and it will die after a couple seconds unless you rev the engine and hold it the gas. Also does it when letting your foot off the gas while driving. I have noticed lately that it has been idling at 600 rpm. It had a tune up around 6 months ago. The only work done on it recently was replacing the starter and fixing a busted radiator pipe. The thing starts fine after it dies, all you have to do is put it in park and turn the key. Just wondering what's the cause and if this is a quick fix or not since it's my only means of transportation.