My 240 is hurtin :(

[240sxjunky]

Hi there, I bought a 92 240sx last year and she ran great. I had an accident with a ditch unfortunetly(was a very expensive lesson to learn). So I had it taken to a personal mechanic, he fixed up all the body work and under carrage. When i drove it home from his place an hour out of the city it started up fine and dove nicely, ended having water in the gas tank for storing it for winter so i removed that. When i got it saftied in the city i got it back flooded, not too sure how, just wouldnt start so checked spark and such, luckily i had some new spark plugs to throw in after removing the gas. I also found gas in the oil so changed it twice, only cuz this dude didnt change the filter so it got super dirty super fast, so i changed it oil is still clean. I did end up drving around a day after the first change with the second batch of nasty oil.

Sorry about the semi long story, anyways, I've been having a problem with it since i've gotten it back, it drives nice when i first start driving, then aventurally after about 5-10 min of driving when i let off the gas the rev's drop super low to about .5 sometimes even lower till the engine cuts out. I know it's pretty hard to understand wats wrong with it without looking at it, but is there anything that it could be or most likley could be? please help!

[rotorimp]

IACV-idle air control valve--the get gunked up and are not able to modulate idle very well.