Ive got a factory 5spd and if I start it and drive it for a few minutes it will sputter and die and want restart till the next day. Weve done the ecu mod and still no luck. Any ideas???????? Also the ECU only has about 135k miles on it.

 

I think your going in the right direction with the fuel system. When was the last time the fuel filter was changed? How long will it idle without dying? Does it die when it revs beyond a certain amount?

 

With ECU's, it's not the mileage that matters. It's the age. There could be a 92 SC400 with 40k miles and need a new ECU where a 99 SC400 with 350k miles, the ECU is still ok. The capacitors leak with age, not miles. Crack it open, check it out for leaking caps.