My 98 Maxima stumbles in 5th gear at 2000 RPM. I just replaced the clutch last weekend and have not yet adjusted the freeplay. But that shouldn't make the engine stumble.

There were two long wires on a sensor at the back of the 5 speed transmission where the plastic harness connector broke when I removed the transmission. The plastic connector was located at the driver side engine mount . Does anyone know what sensor that is? This sensor is located in the area of the starter motor on the transmission, a bit lower and farther back.
I used spade lugs to reconnect them and they may not be making contact.

Can anyone tell me what's going on?

 

Have you checked for any stored error codes?
A stumble is usually a misfire. Check your work, make sure both crank sensors are clean. Check all electrical connections. Did you clean the mating surfaces when you put the tranny back in? Sounds like the sensor in question might be the speed sensor.

 

Thanks, I will check the codes. maybe the ECU is relearning as I removed the battery for the clutch removal?