engine trouble

my wife's 98 altima gxe w/ 137k miles will crank but die after warming up. just before it dies all lights go dim. just before the engine trouble i noticed the radiator fans blowing extremely hard. had a similar problem before but there was excessive gas burning and a strong gas smell when the problem would occur, engine would lose power, then jerk real hard and accelerate then die down again and shut off. nissan said fuel injectors, autozone's test said multicylinder missfire, one mechanic said onboard computer(changed but didnt fix the problem) another mechanic said temp sensor(changed but didn't fix problem either). didn't drive it for couple of days and when i did it ran fine until now which has been about a year and a half. if anyone has experienced anything like this and can steer me in the right direction, i would really appreciate it. this time around i dont want to spend a lot of money on trial and error again. thanks in advance

well i had a problem where my lights would dim then the car would die; it was my alternator. have advanced auto parts check that out if they can, or go to a mechanic and have it checked out; just my two cents