If you`re concerned about fuel economy but the mini Geo Metro fits like a corset, there`s a host of high-mileage cars on the market that skimp on gaswithout skimping on the simple pleasures.

A trio of `91 small cars arrived for testing-the Nissan Sentra andChevrolet Corsica and Cavalier-each carrying an above-average mileage rating, but none of which has to be hidden behind the recycling bin in the garage for fear the neighbors will label you cheap.

Sentra is all-new for 1991 and Corsica and Cavalier are carryover modelswith minimum change.

We drove the performance Sentra SE-R, which is offered only as a two-door coupe and only with 5-speed manual; the Corsica LT four-door sedan with 4-speed automatic (5-speed manual standard); and the two-door Cavalier VL(for value leader) coupe with 5-speed manual (3-speed automatic optional).

Of the two cars we drove with manual, the Sentra 5-speed was a pleasure-smooth easy movement with no notchiness, balkiness or hesitation. The 5-speed in the Cavalier became more arthritic and loud the more we drove.There`s only one smooth 5-speed in the GM stable, and that`s in the Saturn.

In overall performance, the Sentra also stood out. The 2-liter, 16-valve, 140-horsepower, 4-cylinder engine is the one offered in the new Infiniti G20from Nissan`s luxury division, which means it`s quick yet quiet, a livelynumber that skips away from the light ahead of the pack but still is rated at 24 miles per gallon city/32 m.p.g. highway.

Base engine in Corsica is a 2.2-liter, 4-cylinder. Our test car came with the optional ($685) 3.1-liter V-6 that develops the same 140-h.p. as theSentra`s 4-cylinder, but has to move about 300 more pounds.

The 3.1 is lively teamed with the optional 4-speed automatic ($540), butSentra`s 16-valve 4 is quicker. The 3.1 carries a 20-m.p.g. city/27-m.p.g.highway rating. With 5-speed manual the rating is 19 m.p.g. city/28 m.p.g.highway.

Look at those numbers a second. With automatic you get 1 m.p.g. more than the manual in the city and only 1 m.p.g. less on the highway. Is 1 m.p.g. moreon the highway worth suffering through five gears in rush-hour traffic?

The Cavalier VL was equipped with a 2.2-liter, 95-h.p., 4-cylinderdesigned for mileage. When moving from the light, the VL seemed impressive,until we realized exhaust sound effects made the engine appear more livelythan it was. If a 24 m.p.g. city/35 m.p.g. highway mileage rating is moreimportant than a 0- to 60-m.p.h. time, the 2.2 liter serves its purpose. With automatic ($465), the 2.2-liter 4 is rated at 24/32.

Ride and handling again finds Sentra the leader. Smooth without beingmushy, firm without being harsh. Sentra sits fairly tight and flat on thepavement in turns and corners. Corsica also is smooth, but you detect moresway and lean in turns and corners. Cavalier offers adequate ride andhandling. You`ll find the center console comes in handy as an elbow rest when making a turn and you and the car lean.

For safety, Sentra offers antilock brakes as a $700 option, but no airbags. Corsica offers driver-side air bag as standard, but not antilock brakes.Cavalier offers neither.

Roominess is about the same in all three. Good room up front, butslightly tight leg and head room in back, especially in the Sentra andCavalier coupes. In all, the cargo or trunk area was massive for holdingluggage or groceries.

The styling nod goes to Sentra. The Japanese subcompact for too longlacked visual substance-a tin can on wheels. The `91 remake is rounder andmore aerodynamic and a pleasant-looking number. The SE-R adds a sporty decklid spoiler. Sentra is built on the same 95.7-inch wheelbase as the `90 model,but is two inches longer at 170.3 inches. Those two extra inches look like twoadded feet.

Corsica is one of the more style-conscious Chevy models. It gets goodmileage without looking like an economy ca r. One glance, especially in allblack with red striping; it looks like a little luxury car.

Cavalier needs a design overhaul.

As for price, Cavalier is the winner with a base of $7,995 for the two-door VL coupe.

Standard equipment includes power brakes and steering; bodyside moldings; 14-inch, steel-belted, radial tires; remote driver`s mirror; and stainlesssteel exhaust.

Our test car added electric rear-window defroster for $160; airconditioning for $730; and a preferred equipment package consisting of AM-FMstereo with digital clock, color keyed mats, dual mirrors (left remote) andtinted glass for $500. With a $455 freight charge, the sticker read $9,840.

The Corsica LT sedan had a $10,070 base.

Standard equipment included power brakes and steering; driver`s side airbag; tinted glass; stainless steel exhaust; AM/FM stereo with digital clock;14-inch, steel-belted radials; and intermittent wipers.

Added were rear-window defroster at $160; automatic transmission at $540; 3.1-liter V-6 at $685; sport-handling suspension for $395; and a preferedoption package including air, AM-FM stereo with cassette and clock, powerwindows, power door locks, speed control, tilt wheel, intermittent wipers,power hatch release, and color-keyed carpeted mats for $2,036 (minus a $600discount). After adding a few more gingerbread items, such as a gauge package for $139, the sticker came to $13,660. Add $455 for freight.

The Sentra SE-R starts at $10,970.

Standard equipment includes power brakes and steering; tilt wheel; remote trunk/fuel filler lid/hood release; rear- and side-window defrosters; sport-tuned suspension with front and rear stabilizer bars; intermittent wipers;14-inch, steel-belted radials; and fog lamps.

Options are minimal. Add $700 for antilock, $825 for air, $800 for apower sunroof and $50 for a leather-wrapped steering wheel, which brought the sticker on the test car to $13,345 plus $275 for freight. Any radio isoptional.

The most serious flaw of the three was up in Sentra. The sewn lipsurrounding the carpeted floor mats is too thick. We depressed the clutch toshift and when we released the pedal, it caught on that thick carpet lip,sticking to the floor. Not a pleasant situation. After moving the mat to head off the problem, it bunched up under the gas pedal.

If you`re still looking for a gift for the high school or college grad,the Chevrolet Cavalier convertible or Plymouth Laser coupe would be apropos.

The grad probably would favor one of each, but unless the offspring justmatriculated from medical or law school, he or she will have to settle for oneor the other.

Chevy, you may recall, dropped the Cavalier convertible in the 1990 model year when it planned to offer a ragtop version of the Beretta. The Berettaconvertible never materialized, which was great news for Pontiac, which pickedup the slack- and more than a handful of Chevy customers-with its Sunbirdragtop.

As of March, the Cavalier convertible is back for 1991 and joins a trioof ragtops at Chevy that include the Geo Metro ($10,000), Camaro ($20,000) andCorvette ($40,000).

When the car arrived to test, we expected to focus on the easy to lower/raise top with its plastic rear window, but found that the 3.1-liter, 140-horsepower V-6 engine that powers the subcompact Cavalier RS convertiblestole our interest. With the 3.1, the convertible delivers a lot of funwhether the top is up or down. The convertible feature just makes a fun carmore fun.

The front-wheel-drive Cavalier was spirited with the 3.1. A five-speedmanual is standard, a three-speed automatic optional. Our car came with theautomatic, which did nothing to rob the performance.

The mileage rating is 19 miles per gallon city/28 m.p.g. with manual and20/27 with automatic.

A Z51 suspension package is standard and includes 14- inch tires, rearstabilizer bar, beefed-up springs and shocks and quick-ratio power steering.The suspension package complements the 3.1 V-6. The quicker the wheel respondsto steering input from the driver, the more the tires grip the road, theflatter the car sits in turns, the less the car jostles the occupants onstraightaways and the greater the feeling of driver control.

Two problems plague the car, however, both resulting from it being aconvertible. The wraparound canvas sides make for a blind spot when pullingout to pass or trying to park. And in our car, the top went up and downadmirably without bruising knuckles, but the right side latch required anextra shot of oomph to lower it into the holder when the top was raised.

As with all convertibles, keep in mind that the top hardware will robrear-seat room and trunk capacity.

And if you`ve never driven a convertible before, the best time to dropthe top is early morning or in the evening after the sun goes down. Lower the top at midday when the temperature is in the `90s, as we recently experienced,and you`ll learn what the inside of a microwave oven feels like.

Worse, lower the top at midday and return an hour later; when you plopdown on the vinyl seats you`ll be thankful there is no top in your way toblock a retreat from the car. Whoever said man can`t fly never sat on a sun-heated vinyl seat in a pair of shorts.

Our test car started at $15,214.

Standard equipment includes power brakes and steering, AM/FM stereo withdigital clock, power windows and door locks, tinted glass, stainless steelexhaust and visor vanity mirrors.

Options called the Preferred Equipment Package No. 2 included airconditioning, electronically tuned AM/FM stereo with cassette and digitalclock, cruise control, tilt wheel, color-keyed floor mats and intermittentwipers for $1,388. Our car also had a compact disc player for $256, whitevinyl bucket seats for $75 and four-speed automatic transmission for $495. Thesticker, minus a $650 discount on the option package, totaled $16,778 to whichyou add a hefty $475 freight charge.

Neither anti-lock brakes nor a driver-side air bag are available.

The other charmer we tested was the Plymouth Laser coupe, a car that haslost a shade of its luster now that Chrysler said it will discontinue it afterthe 1993 model run.

The public warmed up to the Mitsubishi Eclipse and the Eagle Talon, theother two members of the subcompact sport coupe trio built at Diamond-Star in Downstate Normal, but the Laser proved to be odd man out. Fine car, but itdidn`t get the promotion and attention from Chrysler Corp. that it deserved.

The front-wheel-drive Laser boasts low cost and high mileage, yet sportylooks-attributes that should attract a graduate not wanting to take on 60months of debt while awaiting the first of what is hoped to be a long seriesof steady paychecks.

We drove the base model Las er hatchback coupe. Though it`s the line`sentry-level model, the car doesn`t look like an economy special that Mom orDad would pick out based on their priority of spending as little money aspossible on the grad`s commuter car.

This Laser is powered by a 1.8-liter, 92-h.p. 4-cylinder engine teamedwith a five-speed manual. Though only 92 horses, all are thoroughbreds. Thefive-speed is a buttery smooth short-throw unit that isn`t burdened by anynotchiness through the gears.

The suspension is sport-tuned. You`ll have to put up with a little roadharshness, but not to the point your can of soda or cup of coffee resting inthe console holder will spill.

The Laser with 1.8 and manual is rated at 23 m.p.g. city/32 m.p.g.highway. With automatic, the rating is 23/30. Good performance, above-average looks and great mileage-hard to beat.

Standard equipment includes power brakes, stainless steel exhaust system, AM/FM stereo with clock, dual visor vanity mirrors, trip odometer, remotefuel-filler door and liftgate release, tilt steering, tinted glass, dualremote mirrors, intermittent wipers, bodyside molding and motorized shoulderbelts. No air bag, but anti-lock brakes are a $925 option on RS models.

Options on the test car included a package costing $1,407 that consistedof air conditioning, power steering, rear-window defroster, wheel covers,floor mats and console cupholder. A radio upgrade with cassette ran $170. The sticker read $12,441 plus $368 for freight. Automatic transmission would have added $688.

>>1991 Cavalier RS ragtopWheelbase: 101.3 inchesLength: 182.3 inchesEngine: 3.1 liter, 140 h.p. V-6Transmission: 5-speed manual, 4-speed automatic opt.Fuel economy: 19 m.p.g. city/28 m.p.g highway manual, 20/27 automaticBase price: $15,214Strong point: Surprising power from 3.1 liter V-6. Easy to raise/lower power top. Open air motoring.Weak point: Blind spot from canvass top, no ABS brakes or driver sideair bag.>>