When I sold my first car, a '55 Chevy, I nearly wept. How could I ever replace those reliable six cylinders that pulled me through snow, sleet and heat of day?

When I sold my second car, a '58 Rambler, I smiled. Good riddance to that lurch in second gear. Farewell to the case of oil I had to carry in the trunk, the better to feed the crankcase a quart every 30 miles.

When I sold my third car, a '60 Volkswagen, my last act was to give it a good, solid kick in the fender. "Rot in hell, or wherever you plan to end up," I cried. "Go shimmy at 40 miles an hour and break fan belts every week for somebody else."

Shouting at my VW gave me immense satisfaction. But not as much as Rita Torelli of Annandale got from writing her Former Fairmont a letter.

That's right, sports fans. When Rita finally unloaded her car last month, she took out four years worth of frustration by writing the heap of junk a "Dear John" letter. It's florid in its fury, poetic in its pique. Some excerpts:

"To my ex-1978 Fairmont:

"It is with very little regret that I turn you over to the custody of a strange new dealer. You have been nothing but one large, brown, cheap piece of bad luck since April 16, 1979, when I had the misfortune to let you in my life . . . .

"During the four years I have had you, I have spent a whopping$3,230.29 for repairs to try and keep you in respectable operating condition. . . . I won't attempt to count the times I have cursed you and wished death on you for stalling, refusing to start, dying on a crowded street in rush hour, skipping, pinging, bumping, creaking, falling apart and generally running like a 1921 tractor.

" . . . You have been replaced by a more faithful, younger, durable, better-looking quality car. . . . I'm sure whoever gets you will be more sympathetic to you than I was. I really hope I never see you again. You'd only bring back bad memories.

"Sincerely, Rita Torelli, A Dedicated Toyota Owner."