A crackdown on commuters who illegally use the Dulles Airport Access Highway, proposed by the Federal Aviation Administration for June, has been delayed and may not go into effect until late August or even late September, FAA officials say.

Rep. Frank Wolf (R-Va.) and other local officials, who spoke out against the FAA crackdown earlier this year, are seeking to have the FAA modify its plan to control the number of commuters using the Dulles access road, originally designed only for airport traffic.

The FAA proposes to allow two- and three-person car pools, identified by special stickers, to enter the access road and proceed east from Reston or backtrack to the airport from Rte. 28 in eastern Loudoun County.

Such low-occupancy car pools would be required to exit the access road at the Beltway during rush hour because of the four-person car-pool requirement for I-66.

Wolf and the Fairfax Board of Supervisors have asked the FAA to allow so-called one-person car pools to use the road under the requirements the agency has proposed for other low-occupancy car pools.

According to estimates made by Wolf, as many as 8,000 people use the access road for daily commuting, by driving to Dulles airport and backtracking so that they can use the limited access highway.

Both Fairfax and Loudoun counties' board of supervisors protested earlier this year that the crackdown was ill timed and requested the FAA to delay putting its proposal into effect until the Dulles Toll Road is completed in fall 1984.

But the FAA, concerned that the access road when linked with I-66 this fall will tempt even more cheaters, would like to get illegal backtrackers off the road before that date.

I-66 operates under rush-hour four-person car-pool restrictions, and highway officials say they will not be able to enforce those restrictions if backtracking commuters use I-66 under the guise that they are legitimate airport traffic, which has no restrictions on the number of persons in a car.

So far, FAA officials appear skeptical. "We are taking a look at their comments, and we are obliged to consider them," said Frank Conlon, manager of the FAA's engineering division.

"We are faced with two alternatives, either eliminate all commuters or accommodate as many as we can. Our projections show many would be accommodated by the two-person car pools."

But area leaders vow they will pursue with the FAA a plan that would put no limits on the number of people in a car.

"I have constituents who live out in the country or because of their jobs can't find anyone to car pool with," Loudoun County Supervisor Betty Tatum (D-Guilford) said.

"I think the FAA has got to look at more than just their personal, little road there and take into consideration the whole traffic picture in the area. It's going to make an almost intolerable situation on Rte. 7 impossible."

The Loudoun County board is expected to endorse Wolf's proposal to expand the rule to include one-person car pools when it considers the FAA rule tomorrow.

FAA officials said they will accept public comments on the access road rule until July 22 and they hope to make a final decision on the rule by the end of August.