I have a 95 G30 van with the 4.3 V6. Stopped suddenly in reverse and started running rough. barely made it home. Noticed IAC was opening too far and moving sporadically. Replaced it and intake gaskets. Also replaced TPS, CTS, MAP sensor and O2 sensor. No change. Checked plugs and wires, retimed. Still no change. Changed throttle body gasket. I have noticed when I remove vacuum line to MAP and plug vacuum port it is at least drivable but runs a little rough and stalls occasionally. Anyone have any ideas?

Could be a vacume leak or bad PVC valve or egr

Finally got the fuel line adapter so I could check the fuel pressure and voila! The rubber hose connecting the fuel pump to the fuel line was split and releasing fuel back into the tank. Replaced it and the fuel pump while I had the tank down and it runs better now than ever.

thanks for updating your fix