98 350 Vortec in 87 Suburban sluggish

Title says it all, Stock tranny, though rebuilt. Can't quite remember the gearing I know it's high and was quite popular in the mid 80's blazers. I think it's 3.71??? I know just enought to be dangerous.
Anyway I get great fuel economy but not much on the take off.
The rear 2 Oxygen sensors are not hooked up.
would a custom chip help fix this? or is it my gearing?
should i try to hook up those last 2 sensors, It would be a pain trying to bore and thread into the exhaust.
Need some info from someone who knows alot more about Vortec engines than I do.
Thanks

First of all bad/uphooked O2 sensors will give you bad engine proformance. I have a JET chip and I can tell a little. I have higher shift points and my timing is advanced.


The computer is your friend treat him like one. If you make him your enemy he will win.

You will never get it to run right without the computer getting all of the information that it is desighned to have. The days of disconecting the emmission controls are over for these newer high tech engines.