Service Engine Soon Light

Allright, I'm new to this forum so please forgive me if I screw up. :)
I'm having an issue with my wife's 96 GMC Jimmy. The problem, per an OBDII scanner is that the Mixture is to Lean on Bank 1 and 2. I just replaced my O2 sensors on Bank 1 Sensor 1 and Bank 1 Sensor 3. Could this have something to do with it? I am not sure how to correct a "Mixture To Lean" Scenario.

Any advice would be much appreciated.

thanks,

--mark

DID YOU DISCONECT THE BATTERY FOR ATLEAST 35 MIN SO THE COMPUTER WOULD RESET.

Yeah, I tried disconnecting the battery to clear the Computer. No luck. I ended up taking it to a buddy of mine who used his OBDII scanner on it and we found that there was a Vacuum line just off of the intake plenum on top of the throttle boddy that had come off. Put this back on and it started running bettr. I passed emissions now and I'm happy.

Thanks the the suggestion.

--mark