Tooburns

Hey guys,

i have a small problem on my b16b when i drive on the highway cruising in 5th gear between 3k and 4k rpm the car will lost power, it dont feel like missfire but more like you lift your foot from gas. If i give more gas it take it and rev good, same if i let go it just came back to normal. Also i noticed it is worst when the car is really hot and i can feel a lost of power in every gear always between 3k and 4k rpm but it i can real feel it in 5th.

I use that car mainly for lapping, on the track engine run strong, no missfire*, no smoke, doesn't burn any oil.

*Only once we had a red flag i had missfire (no check engine) when we started back, i went in to the pit let it cool for 1 min, shut down the car, started back and no more missfire for the whole day.

Spark plug, wire, cap and rotor are brand new

Stock b16b ecu

In 96 Civic

Engine is freshly swapped (june) and doing it since day 1

Im trying to figure out where to look because i have no idea and i cant find someone with the same problem that got it fixed.

thx guys !

m4xwellmurd3r

O2 sensor maybe? If the sensor starts throwing bad values the car wont think anything of it and itll start miss fueling the car during closed loop

Tooburns

thx i might try an otehr o2 sensor

any other advice on what can cause that ?

ShinsenTuner

iTrader: (1)

If its losing power or "bucking" it's leaning out in that area. Like stated before either your o2 sensor is acting up or you have other problems in terms of fuel and ignition.

the171

a wideband would be a good investment. then you can stop guessing if your getting the right air fuel ratio or o2 sensor readings. an o2 sensor can last a long time though. 20+ years.

Adding additional grounding points has helped me smooth out motors before. Ive also had electronics inside the distributor go bad causing random hesitation. You can replace with parts from the junkyard for little more than free. I've also had worn plugs cause sluggishness during cruising. but you said those are new.