MAP or O2

[alphatonic]

To me it seems if I trick the O2 sensor to not pump more gas (94 obd1 Silverado) I wouldn't need to trick the MAP too... am I wrong??

To properly adjust a MAP it would have to constantly fluctuate with the throttle. These MAP enhancers I see usually have one or two settings (highway/town) then leave it alone... To me that just doesn't seem efficient at all. Its either going to be running lean (which is real bad on a motor) or run rich (which is bad on my pocket) Unless im going 55mph or just idling thru town, the enhancement isn't going to be exact....
And who the hell wants to or could remember to adjust the damn thing EVERYTIME you get off or on the highway?!?!

[antihero]

The problem with "fooling" only the O2 sensors is long term fuel trim. EFIE's increase the voltage going to the computer to compensate for the hydrogen which will cause a lower voltage from the O2 sensors. EFIE's work until the long term fuel trim re-calculates. It sees that for a given amount of air flowing into the intake, the injector pulse width should be x amount of time and will adjust. This is done by the vehicle computer to compensate for ageing sensors and other outside conditions. The commercially available EFIE's are not always the greatest. A simple linear OP amp circuit that amplifies proportionally to the input voltage is what is needed.

[ultra_efficient]

To me it seems if I trick the O2 sensor to not pump more gas (94 obd1 Silverado) I wouldn't need to trick the MAP too... am I wrong??

To properly adjust a MAP it would have to constantly fluctuate with the throttle. These MAP enhancers I see usually have one or two settings (highway/town) then leave it alone... To me that just doesn't seem efficient at all. Its either going to be running lean (which is real bad on a motor) or run rich (which is bad on my pocket) Unless im going 55mph or just idling thru town, the enhancement isn't going to be exact....
And who the hell wants to or could remember to adjust the damn thing EVERYTIME you get off or on the highway?!?!

use a Apexi SAFC2, it handle both MAP and back O2 sensor. best thing in the world to tune a truck like yours. ask a few tuners about ur truck and using a SAFC2 to tune it.