First, my Integra LS has about 152,500 miles, the transmissions seems to hit really hard even when taking off slow, I noticed at one point I was actually shifting and while I was in 3rd it went about 5300rpm it dropped down to 4800 then went back up. Is this normal? I haven't changed the tranny fluid yet, so do you think that may be the problem? Also, my gas mileage is horrible, I am getting about 18-20 mpgs, could this be because of a bad O2 sensor? My CEL came on and I got a code 61, which is a bad O2, or do you think there is another problem.

Thanks for your help!

 

Yes, you definitely need a new O2 sensor. I replaced my original one w/ 240K miles on it, and I didn't even have any CEL's, but still saw a 4-5 mpg increase across the board.

 

Yeah I just got a new O2 sensor but haven't installed it yet, I'm just concerned about the tranny.