I would look especially close at the rubber lines near T-case output. They have a tendancy to get grease on them and deteriorate. Also, make sure your filler neck is connected. And the clamp is tight. One other thing to look at if you have the carb motor,is the canister purge valve. I think it is on the PS fender. It should be the one that is connected to the canister via a vacuum line. I believe it is normally closed. Therefore, when no voltage is applied it should not pass any air. A vacuum pump would be best for this test, but you may be able to blow into one of the lines with the other one dosconnected and see if any air passes. Do this with the key off. If you have the RE motor, there is no purge valve. If that is the case, the tech would have to pinch both the canister vent, and the purge hose. If you find no other problems, i would make sure that part of the test is being done correctly.