Even Toyota makes mistakes. Not often, but every once in a while, the Japanese automaker flubs just like the rest of the industry.

The Previa mini-van is the most recent blunder.

For the 1998 model year, Toyota has corrected that, dropping Previa for the Sienna.

What was so bad about Previa, other than the name? Well, it stood too tall and thin, perfect for narrow Japanese roads and narrow Japanese people, but corset-like for Americans raised on cheeseburgers, chips--no fries--and Pepsi--no Coke.

Previa also was powered by a 4-cylinder engine known more for puttering than performance and was a rear-wheel-drive van in a front-wheel-drive world. OK, RWD is better for towing, but tell that to the owner of a 4-cylinder engine.

Worse, however, on some earlier models, when you needed to check or add transmission fluid or oil, you approached that service from within the cabin rather than lifting the hood and attacking it from the traditional in-your-face position. Operating on Previa was like removing tonsils through your foot.

And Previa carried an optometrist-friendly price tag, because once a consumer saw the sticker, he or she would need their eyes pushed back in their heads.

Sienna is just what was needed--10 years ago. It is longer than the regular-length Chrysler mini-van but shorter than the extended-length version. There are no plans for an extended-length Sienna, Toyota said.

Sienna is built off a stretch of the popular and successful Camry platform, which means it is produced at Toyota's Georgetown, Ky., plant. Toyota refers to Sienna as the "Camry of mini-vans."

It is a front-wheel-drive machine that also borrows Camry's popular V-6. It sits lower and is 3 inches wider and 6 inches longer than Previa. More important, if surgery is needed, you lift the hood rather than remove the front seat.

Best of all, the price is more in line with reality. Sienna is offered in CE, LE and XLE versions that start at $21,140, $23,500 and $27,100, respectively. Previa started at $24,878 for the base DX, $29,528 for the uplevel LE.

Previa came out in 1990 as a 1991 model. It was a rush job, a hurried reaction to the fact that domestic automakers had invented a mini-van market and the Japanese were caught without vehicles for U.S. roads and U.S.-shaped people.

Sienna is about the last FWD mini-van to reach the U.S., a rarity for an automaker usually known for leading the pack. Waiting had one benefit though. It allowed Toyota to copy the best features from existing vans and add a few of its own among those lacking in the competition.

So, unlike Ford, which brought out the Windstar without a driver-side sliding door, Sienna will offer one. Windstar won't until 1999.

And one of the more popular mini-van features, and the one that's helping General Motors mini-vans attract sales, a power passenger-si de sliding door, is on Sienna's option ($375) list--though not until February or March.

The Sienna CE and LE are offered in three-door (a passenger-side slider) or four-door version (passenger- and driver-side slider); the XLE is only a four-door.

Sienna's 3-liter, 194-horsepower, 24-valve V-6 performs well, as it should being lifted from Camry. It provides ample power, is quiet and is rated at a respectable 18 m.p.g. city/24 m.p.g. highway.

In testing Siennas CE to XLE, however, we can't help but feel that if you have the cabin filled with seven people or loaded with luggage, the V-6 is overmatched when climbing inclines or merging quickly onto the interstate.

The suspension is above average. The vehicle sits rather flat and minimizes body roll and lean in corners. We spent some time in the back of the bus and found you could travel in the third seat without lots of up-and-down movement as punishment for your choice of seating locations. A d a power vent window in back helps air circulation in the cheap seats.

There's also more of a go-where-you-point-it feeling in Sienna than in a Chrysler mini-van, for example. Sienna comes with variable-assist power steering, which feels rather light at low speeds.

The vans come with p205/70R15 tires as standard. A wider-profile p215/65R15 tire is standard on the XLE, optional on the LE. For optimum road grip, we'd reach in the wallet and get those tires.

Sienna exhibited good road manners and stability, and even at 75 m.p.h., there wasn't a lot of jarring or bouncing around.

A gripe, however. The cabin design allows easy pass-through from driver/passenger seat to the second seat as well as easy access to the second seat from the slide-open side door. But if you try reaching the third seat from the side door, it's a squeeze and the running board that's supposed to help you up is far too slender for EEE shoes to manage.

As we said, in being late to market, Sienna has a few goodies the others don't, such as cupholders that fold down from the sides of the second row of seats. What's so unusual about cupholders? If the kids step on these, they collapse without breaking and return to their normal shape. Neat touch.

And Sienna has a ton of cup and juice-box holders to service every passenger. Not unique, you say. True, but Sienna also has water-bottle holders built into the rear side walls for those who never leave home without H2O. Who said only BMW catered to yuppies? Novel touch.

Also, fold any of the seat backs, and they become plastic-top tables; there are almost as many stowage bins as cupholders; the tire jack is in the rear sidewall out of sight, but within easy reach; a power plug is in the sidewall for the second or third row of passengers to engage in video games or practice on their laptop while another power plug is below the dash for Dad or Mom.

Also, a coin tray is located left of the steering wheel; nets along the driver and passenger seat allow you to carry CDs; the second seat back can be folded over and used as footstools by third-seat passengers; and second and third seat backs recline so any passenger can relax. Nice touches.

A tire-pressure warning system signals under inflation; a child-restraint seat, coming for midyear, removes for cleaning; a storage drawer (borrowed from Chrysler) pulls out from under the passenger seat on four-door models; and there's a holder for sunglasses or a garage-door opener in the ceiling.

Borrowing from Chrysler, the driver-side sliding door stops opening if the fuel-filler door is open to keep them from colliding.

Dual front air bags and anti-lock brakes are standard.

The base CE also adds intermittent wipers, auto-off headlamps, foldable outer mirrors, plastic lower-body cladding and remote fuel door release.

The LE adds power windows/door locks/mirrors, cruise control and rear-window defogger. The XLE adds second-row captain's chairs, heated mirrors, leather-wrapped steering wheel, dual illuminated vanity mirrors and keyless entry.

The LE and XLE also offer an interior lighting system that automatically shuts off if accidentally left on more than 30 minutes to preserve the battery, as well as high solar-energy absorbing windshield and front side windows to keep the cabin cooler.

They also offer standard privacy glass, power rear-quarter windows, rear-window defogger and front/rear air conditioning. The XLE adds standard heated outside mirrors and a roof rack.

Among popular options, the power moonroof runs $980; child seat, $250; captain's chairs, $650.

The question is: Will those who paid a king's ransom for a Previa and got a narrow, under powered, spartan machine, be willing to give Toyota a second chance with a wider, peppier, far better-equipped Sienna?

And will the personst ll making payments on a 3- to 4-year-old Previa be willing to assume debt on that Sienna?

Toyota forecasts sales of 65,000 to 75,000 Siennas for 1998.

>> 1998 Toyota Sienna LE mini-van Wheelbase: 114.2 inches Length: 193.5 inches Engine: 3-liter, 24-valve, 194-h.p. V-6 Transmission: 4-speed automatic EPA mileage: 18 m.p.g. city/24 m.p.g. highway Base price: $23,500. Price as tested: $24,475. Includes $650 for cloth captain's chairs, $30 for heated power mirrors, $85 for full-size spare and $210 for roof rack. Add $420 for freight. Pluses: Longer, lower, front-wheel-drive, V-6 replacement for shorter, taller, rear-wheel-drive, 4-cylinder and extremely costly Previa. Built off modified Camry platform and powered by its V-6. Convenient walk-through to second seat. Copied all the good points from FWD mini-vans. You don't need to rip the cabin apart to perform service or make mechanical repairs. Dual air bags, ABS and cupholders that bend, but don't break. Water-bottle holders, too. Minuses: Automotive giant is last out with an affordable FWD mini-van. No power sliding passenger door or built-in child restraint seat until mid-year. No traction control. Slippery step for rear-seat entry/exit. >>