I have a 2001 isuzu rodeo 2.2L 2wd manual trans, the car seems to buck or hesitates if you shift into any gear while trying to accelerate. But it only does it around 1200 rpms and then goes away. It's feels like a loss of power for half a second and then everything is fine. There are no check engine lights or codes.
It also does it if you drive in 5th gear (staying in gear not touching the clutch) and drop from 45 to 39mph and then slighly press the gas pedal to acclerate. The rpms are around 1700 to 1800 and then it goes away.
I already change the transmission fluid no change. I also cleaned the trottle body.