Hey I just bought a 1990 300zx back on Nov 1,2006. I just had a new trans put in it jdm trans used. I spent 1,200.00 to fix the car. Now i'm having other issue with my car now. Everytime it rains or the car gets wet i have problems with the idle racing at 2000rpm and the idle don't drop until awhile. The idle is real rough and now my transmission takes forever to shift. Then out of nowhere the car will be fine and if it rains again the car acts up again with the shifting problems,rough idling,eating gas. I got to step on the gas to get the car too shift. I can't just drive the car normally without it not shifting right. Sometimes the car is ok and sometimes it's not ok. The car has me baffled i just wan't to enjoy my new z carand i got to deal with this issue now. But it is strange that everytime it rains i have problems with it shifting and the rpms will fluncuate also when i'm coasting down an incline but i have my foot on the gas a little bit the rpms go up and down when i let off the gas a little when cars in drive. Please someone tell me or think what the problem maybe. I had it looked at and my mechanic thinks it has a bad afm. I have already replaced the tps and that wasn't it. It is driving me nuts i just want the car to be ok. I'm about to order a afm but i want to get some advice on the problem with the car. If anyone has a ideal what it can be but everyone i has spoked to so far is saying the afm is bad causing the car not to shift properly and having a rough idle and also the racing of the rpms. If anyone has an ideal let me know. Thanx Donnie's 1990 300zx. NEW JERSEY. Email me if anyone might have a solution to this problem. Email is snipped-for-privacy@aim.com