running rough between 2-3 grand after 20 min running

[farm180]

Good day everyone
92 nsx
48000 miles
between 2-3 grand after the car is running for 20 min its starts to sputer and fells like stalling :frown:

so far i checked
air sensor
spark plug no oil
checked for oil leaks none
coils amps ok
fuel jets preasure ok
filled gas tank twice using differnt stations
added fuel assistance in case i had water

what else ? anyone please

 

[pgilliam1]

So your post makes me think that the car runs fine when cold, then after it warms up it misses. Sounds maybe like an O2 sensor. When the car runs bad, disconnect the O2 sensors and see if that makes it run correctly.

When the engine is cold the ECU runs in Open-Loop mode and doesn't use the sensors. Once warm, the ECU runs in Closed-Loop mode detecting the O2 sensors.

It could also be your fuel pump resistor. If the car runs fine over 4K rpm then I would short the resistor connector to hold fuel pressure at max and see if that helps.

Good Luck, and be sure to post the fix.

 

[farm180]

thanks
i will keep you posted

 

[mr_goat]

I had this problem. The shortening of the fuel pump resistor fixed the problem but I replaced the fuel pump too. Runs great now :smile:

Good luck!