My 1996 Buick Regal seems to have an intermittent problem and sometimes won't start when I happen to have the air conditioner or even just the vent air on. I don't know much about cars but the engine won't turn over and it appears that it's not getting any gas. However, it seems to start just fine if I happen to remember to first turn off the a/c, heat, vent or any interior temperature controls. As a rule, if I go back about 15 to 30 minutes later with the a/c already off, it then starts just fine.