Nissan Repair: 93 Nissan 300 ZX, nissan 300 zx, nissan 300zx

Question
Hey, I have a 93 nissan 300zx with about 95,000 miles on it. I have had nothing but problems with it since I have gotten it. First I replaced all the plugs and cleaned the k&n air filter, then the timing belt and water pump replaced, then all six injectors were replaced along with the fuel pump. This car has been a huge hand full and yet another problem...Lately I have been smelling gas. I smell it under the hood or even around the car when I get out, it blows through my vents also. The exhaust smells clean though. I have even taken it to a mechanic and he said he's checked my engine over and cannot find any leaks but it is obvious the smell is coming from the engine bay. I have looked myself along with my dad, still nothing. Also, if this could possibly be connected to the same problem. When I start my car, it never wants to run at first. Such as if I don't drive it all night while I'm in bed it has trouble starting the next day, sometimes it takes three tries to start it and then once its started its tries to die until its been running for a while and I can watch the rpms drop and recover and drop and recover as the car tries to adjust itself. It has the same problem in hot and cold weather...but if say I take a trip to the grocery and its only been an hour since I've driven it last it starts fine. Another thing it does, its get cranky and sometimes I'll be casually idoling at a drive-thrum or something like that and it might randomly decide to rev up to anywhere from 1200 to 2500 rpms, i don't know what to do anymore, is it possibly even a electrical problem? Censor of some kind? The other day it started idoling at about 2500 for no reason and I just let off the brake and see what it would do and it idoled high enough it was able to build up enough speed to switch to second gear without me ever touching the gas in about a 20yd. stretch, haha. I am absolutely clueless and no mechanics are even able to help me, your my last resort. Even if you cannot give me an exact cause a list of some possibilities would be great so I can go to a mechanic and say "hey check this out, i heard this is a possibility."
Thank you so much, sorry this is soooo long but I'm desperate and I wanted you to have all the details.

Answer
Travis,

The gas smell is probably coming from a rotted fuel vent line or the pressurized lines itself.  If you cannot find the line and they all look good then I would drop the tank and look there.  Another place is the evaporative canister under the car that holds gas vapor and fuel when the fuel system pressurizes.  The idle problem is related to the idle air control valve or the power steering pressure switch telling the idle to go up.  I would clean the idle air control valve first.