Could this be a sign of a dead sensor?

[Azn_Outlaw]

Okay I have a 99 Civic EX with an automatic tranny...
at times I get this harsh or eratic shift from 1 to 2nd and then fine from 3rd and on..

but this is the odd thing....if I pull the ECU fuse or reset the computer..

the car will shift normal again....for about another week or so then, suddenly do the same thing..

so my question to yall is..

would this more of a sensor problem....than something wrong with internals?

could it be a either a mainshaft or countershaft sensor is dead?

thanks for your help