I recently started having problems with my truck (94 Flareside 5.0L) so i ran a self test & got back the 172 code. I checked the majority of the sensors that deal with air/fuel mixture & found a couple of things. First, my O2 sensor is no more then a yr old. I probed the O2 sensor connection to check for voltage w/ignition on engine off, got back a big fat Zero. Also, no voltage going to the canister purge solenoid. Truck seems to run fine til it gets warm then tries to die out when stopped at a light. Seems to me that it still running on open loop. How can i fix the voltage problems?

More info: This issue started after trying to do a donut (on dry pavement)
Truck reved up then died out. Cranked it up, kept turning off. Popped da hood, couldnt find the problem. Started disconnecting sensors til the truck stayed on, drove it home with MAF & Air temp sensor disconnected (smell of raw gas in the air). Baught both sensor new the next morning, changed them. In the process i found the intake tube disconnected from the MAF housing. Connected it back up, started the truck and found the existing problems as explained above. Need help, truck burning to much fuel w/horrible idle at times.

Parts changed: spark plugs, fuel filter, MAF & Air temp sensor.