There is a certain snap in MacKenzie Canter's step these days, and he has the kind of anything-is-possible glow that long-shot candidates get in the days before an election.

Canter, nominated to run in Virginia's 10th Congressional District by Democrats who gave him little chance of beating Republican Rep. Frank R. Wolf, has run a low-budget, door-to-door campaign in which he has sought respect as much as votes.

Now, buoyed by the anti-incumbent mood of residents across the country who have been frustrated by Congress's wrangling over the budget deficit, Canter says Wolf is ripe for an upset.

And Canter, who admits he has had trouble raising money from fellow Democrats more interested in the battle between Alexandria Mayor James P. Moran Jr. and Rep. Stan Parris (R-Va.) in the neighboring 8th District, says his campaign's polls show he is running even with or ahead of Wolf in key parts of the affluent 10th District.

The district includes northern Fairfax, Arlington and Loudoun counties, Falls Church and Fairfax City.

"Timing is everything in politics," Canter said.

A 40-year-old Fairfax County lawyer, Canter has criticized Wolf for supporting Reagan-era economic policies and is quick to point out that, unlike the congressman, he supports a woman's right to an abortion.

Canter also has called for higher taxes on the rich and national health care.

"People are ready for a change," said Canter, whose campaign has raised about $70,000. "Frank Wolf represents what people are turning away from."

But political leaders throughout the district, Republicans and Democrats alike, find Canter's claims improbable.

Although Republicans and incumbents have been taking a beating in political polls across the nation, Wolf, who has been reelected by wide margins in recent years, is still viewed by most as a solid bet to win his sixth term representing the district, which is largely conservative.

"I think Mac's running harder and better than most people expected," one Arlington Democratic leader said. "He's gone from being a candidate with no chance to being a long shot. But it would be the biggest upset I've ever seen if he beat Frank Wolf."

Wolf, 51, also faces independent Barbara S. Minnich and jailed political extremist Lyndon H. LaRouche Jr. in the Nov. 6 election.

Wolf has run a customarily low-key campaign in which he has stressed his lengthy record of constituent service, particularly on issues involving transportation and federal workers.

He particularly cites his role in delivering federal money for Metro and in pushing for additional lanes on Interstate 66.

Wolf's campaign, which has raised nearly $450,000, last week rejected accusations that Wolf has dodged Canter by appearing at only two debates with the Democratic challenger.

Wolf and Canter were scheduled to debate a third time on Oct. 19, but Wolf canceled the appearance before members of the Fairfax County Chamber of Commerce, saying he needed to stay on Capitol Hill for House business.

"Congressman Wolf has been campaigning very actively, and the people in his district know that," Wolf spokesman Ed Newberry said. "If {Wolf} had missed some House action by going to that debate, Mac Canter would have criticized him for that . . . . The congressman has been doing the job he was elected to do."

LaRouche, the leading fund-raiser in the campaign with more than $500,000, has rarely mentioned Wolf in television, radio and billboard advertisements, preferring to criticize Reagan and Bush administration policies.

"I'd campaign against Mr. Wolf, but really, his record is inconsequential on foreign policy and national issues," LaRouche said in a recent telephone interview from a federal prison in Minnesota.

He is serving a 15-year sentence for mail fraud, tax evasion and conspiracy in connection with a $25 million fund-raising scheme.

Minnich, a former federal policy analyst from Sterling who has campaigned to raise income tax rates for the rich, has not raised any money beyond a personal donation of $200 and has spent much of the campaign trying to get herself invited to debates.

"It's been somewhat frustrating," Minnich, 50, said. "But I'm glad I {filed to run for office}. It's opened my eyes quite a bit."