1994 cpi everytime the O2 sensor switches to lean the engine boggs down. Help please!!!!

 

The O2 sensors are a representation of whats going on with the engines fuel/air mixture. So the next step would be determining if you trust its readings, or dont. If you dont, then the engine could be running normal, and the O2 is freaking out, since you say its bogging, it would actully indicate a lean condition.

My next step, considering the vehicle, would be in one of two directions... Fuel... or air... or rather.. Checking fuel pressure, and checking manifold vac, seeing how both are failure prone components

1-1.5V MAP At IDLE
4+ At Wide Open Throttle

55-61PSI for VIN "W"
9-13PSI for VIN "Z"

Good Luck!

 

your best bet would be to check out the o2 sensors. on the cpi/ vortecs there is one along the underside of the aircleaner duct and another main one on the drivers side near the manifold it could be on the left aswell depending on the year mine is on the drivers side though. hope that helps. does yours surge when the truck is cold or only when its warmed up. if it does it right off the bat when you start it im tempted to say it could be the I.A.C valve or even the e.g.r valve. good luck.