You won't soon meet a luckier duck than Jeanne Barker, of Herndon. She needed not one, not two, but three knights in shining armor to rescue her from a tough spot. All three came romping forward, right on cue.

Jeanne's troubles began a couple of weeks ago in the parking lot of Fair City Mall. She was backing out of a parking space when her engine started to die. She instinctively stepped on the gas. "All of a sudden," she writes, "the engine started to roar like a launching rocket."

Jeanne turned it off. Then she tried starting the car three more times. Each time, it was Cape Canaveral all over again.

Finally, Knight One came by and asked if he could help. He pushed Jeanne's car back into the parking space, opened the hood, fiddled with the accelerator cable, then smiled and walked away. Problem apparently solved.

The next morning, at 9:15 a.m., Jeanne was driving to an appointment in Bethesda via the Beltway. She pulled into the far left-hand lane to pass, and she stepped hard on the gas. Vrooooooooom!

"I knew I had to get to the right shoulder ASAP and turn the engine off," Jeanne says. Miraculously, she managed to cross four lanes of heavy late-rush-hour traffic and do so.

Up went the hood. And about 10 minutes later, up pulled Knight Two. Jeanne explained what Knight One had done the previous day. K-2 repeated the process, gave Jeanne a wave and drove on.

Jeanne limped into Bethesda, being careful not to give the accelerator any more pressure than necessary. She began calling gas stations there, but she got the usual story. They couldn't get to her car for three days, or they were too busy to get to it at all.

Finally, Jeanne called a Chevron station in Reston. The manager told her to bring in the car the next morning and he'd have a look.

When Jeanne did, the manager quickly became Knight Three. He took a look under the hood immediately and discovered a loose bolt that had apparently been left near the gas cable by a previous mechanic. Somehow, whenever Jeanne stepped on the gas hard, the bolt would land on the cable, causing Canaveralism.

The Reston mechanic pulled and yanked and fiddled and faddled for about 10 minutes. Then he pronounced the job done.

Jeanne asked him how much she owed him. "No charge," said K-3.

Jeanne does not know the full names of any of her three knights. But to all of them, she offers her warmest thanks. She grew up in Idaho and Utah, where such kindness is standard. In the East, knights can be scarce. Jeanne is genuinely grateful that when she needed three of them, they weren't.

American Express has one of the most accurate check-processing operations in the world. According to a corporate spokeswoman, Big Green gets it right 99.8 percent of the time. But a Chevy Chase reader of mine recently joined the .2 percent, in a somewhat disconcerting way.

My reader is one of those people who likes to sit down and pay her bills all at once. The most recent time she did that, my reader wrote out a check for $168 to her downtown Washington parking garage and a check for $356.23 to cover the balance on her American Express credit card.

But then she fumbled. She accidentally mailed the garage check to American Express. And the next morning, she presented the American Express check to the attendant at the parking garage.

The garage attendant picked up the error right away, and my reader immediately wrote out a second check for $168. She assumed AmEx would refuse to accept her other $168 check once it caught the error.

But to my reader's "surprise and amazement," Big Green apparently never noticed that her check was made out to MetroPark. AmEx processed that check, deposited it and listed it in my reader's computer record as partial payment of her $356.23 bill.

"I grew up believing in my heart of hearts that you can't cash a check that's not made out to you," my reader says. She wants to know how and why American Express could do what it did.

Gail Wasserman, public affairs manager for American Express, said my reader was "the one that slipped through the cracks."

She said that 40 to 50 clerks process AmEx credit card payments 24 hours a day, seven days a week. These clerks routinely double-check to be sure American Express is shown as the payee on the face of each check. "The last thing we are is smug about this sort of thing," Gail said.

Bottom line: Always double-check your bills before mailing them. If you think you can't send the wrong check to the wrong creditor, this story proves that you can. And if you think clerks will always bail you out if you make a mistake, you'd better think again.