my 240z 1971 mint condition for some reason wouldn't go past 85 the engine began to bog down as if the ignition wasn't feedin it but i went to fourth and same happened and in 1 and 2 i can all the way to redline but not 3 or 4 just wont go past 85 is there some way it has a govener i don't know about cause my 280zx 83 goes well past 85 without trouble any ideas

 

check the fuel filter, carbie floats and fuel pressure....
i had lots of rubish in my tank and it used to block up the fuel filter all the time ... got it from running hioctane gas

Rusty Datsun x 3