S13 loss of power in 5th gear
 

did some highway driving on my '90 240sx today and while in 5th gear, i was revving up to around 4k and all of a sudden there's no power at all and the car starts decelerating even as i open the throttle. i can't do anything else until i put it into neutral and back into 5th. i try to rev it up again and same thing happens.. this seems to only happen in 5th gear, and maybe 4th too. 1st 2nd and 3rd is fine i can redline it without a problem.
help anyone?

sounds like a faulty vehicle speed sensor.

but why are you going over 140 km/h?

Does it go to "idle" when you lose power?

to be honest not really sure how fast i was going cause my speedo doesn't work hehe

and yeah it kind of does idle.. but its not the same going to idle as if i pressed in the clutch, it kind of slowly drops down on rpm gauge but i can still hear my engine revving if i rev it.

base on the gear calculation your going 140 if you don't have slippage haha.

bingo. check and replace your vss. your speedo will also start working and your ecu won't be fuel cutting at 4k rpm

ahh will do tomorrow..
thanks!
but i don't understand why my ecu would cut off my fuel at 4k rpm if my vss is malfunctioning?

^ malfunctioning VSS is sending signal to ECU that u are hitting top speed

so its fuel cutting as if it was at 7k or whatever RPM normal fuel cut is at

my guess

it's electronically limited to 196

slow down tool and fix your vss like posted above