My 1997 Chevy Blazer failed the readiness test, as well as for trouble codes for EVAP small/large leak. I found a leak in back solenoid. It was not closing. I replaced it. I also replaced the heat temperature sensor, the EGR valve, and the gas cap. I used a vaccum guage to check the EVAP canister to the gas tank. The system held vacuum. All this with still no luck.
I'm wondering if the problem can be with the oxygen sensors. It has 4 of them. 2 O2 sensors up stream each side below the exhaust manifold, one in front of the converter and one after the catalytic converter. They all have 5 volts with key on, engine off. No continuity, and no oms on any off the 4 O2 sensors. If the oxygen sensors are in a open loop will the EVAP monitor run? I'm not getting a trigger signal from the computer to open the purge solenoid or close canister vent.
