Maryland gambled on the Reagan administration's congressional clout last March, deciding to delay putting into effect one of the least popular environmental programs ever conceived by regulators: the vehicle inspection and maintenance program.

So far, the gamble isn't paying off. This inspection and maintenance program involves a check of tailpipe emissions to make sure pollution control devices on cars are still operating properly. In 1979, an EPA study indicated that as much as 80 percent of cars with emission controls were illegally polluting the air, either because the control devices had been disconnected, the engine misadjusted or the motorist was using leaded fuel.

Inspection programs are mandated by the Clean Air Act for any area unable to meet the auto-pollution standards by this Dec. 31. The EPA figures 29 states will be in that boat--including Maryland--and only 16 of them have an inspection program in place or planned.

The states can petition EPA for a five-year extension of the deadline, but "one catch is that you have to put in an inspection and maintenance program," said Richard D. Wilson, director of EPA's office of mobile-source air pollution control.

The idea of someone peering up the tailpipes of their automobiles has never set all that well with the nation's motorists. In 1980, a spiteful Virginia legislative panel, miffed at the prospect of forcing constituents to submit their cars to this indignity, voted to make members of Congress who live in the Northern Virginia suburbs get an emission inspection no matter where their vehicles were registered.

That one didn't make it into law, but the sentiment has been echoed in other states. California did without $150 million in federal highway funds for two years until the legislature finally caved in and enacted an inspection program. In Pennsylvania, a federal judge ordered a halt to federal highway funding because the state reneged on an agreement to start testing emissions.

The EPA's Wilson said the Reagan administration has supported Clean Air Act revisions doing away with sanctions as enforcement tools "because it builds ill will among the states, does not always work and makes them fight even harder."

But both Wilson and associate EPA administrator Kathleen M. Bennett agree that emission inspections can be a useful environmental tool in areas with severe auto pollution problems. And there isn't much sympathy at EPA for the gamblers, like Maryland.

"They were betting on the Congress. They were assuming the act would change," Bennett said. "We don't want to be blamed. They're not the only state in that fix."