I have a '92 2600i 2wd. It idles well when cold, once warmed up it hasa somewhat rough idle (700 rpm); after ~ 10 seconds of idling (like at stoplights), the idle drops to around 600 rpm and it runs very rough. It comes back fine when you step on the gas and will even idle better for another 10 seconds or so if you tap the gas a little. I had the computer replaced (for another problem) and the idle was the same way before/after the computer switch. Anyone here has this and figured it out?