BACK HOME in New Orleans we used to accuse some friends of "goin' 'round actin' all seditty." That meant they were fakes -- born hell-raisers who pretended to be sedate only to fool parents and teachers.

Now, General Motors is offering us the automotive version of "seditty" -- the 1986 Pontiac Grand Am SE.

The car is a glorious phony.

It pretends to be oh-so-o-o-European, so verrry sophisticated. But it ain't nothing but a rip-roaring road-eater that could make some old-time hot-rodders proud.

Those folks handling GM's advertising may go on calling the Grand AM SE "Euro-style." Whatta they know?.

Truth is, this is Detroit metal, people. It's dressed to look like something from Germany. But it's Detroit metal, nonetheless.

Outstanding complaint: A goof in fit-and- finish. That carpeting behind the test model's climate control/stereo console needs to be tucked in. As is, it allows prying eyes to see the console's red, yellow and white electrical wires. A minor but tacky thing.

Outstanding praise: Driving characteristics. This is a hummer, a street hustler. My goodness, this car can run!

GM's engineers used muscle-car philosophy to build this one. They took a relatively lightweight body and stuffed it with a powerful engine -- a 3-liter V-6 enhanced by multi-port fuel injection.

Fuel injection more precisely meters the fuel entering the cylinder combustion chambers. The metering yields a better mix of fuel and air, a more complete burn of the mixture, which means more power, better fuel economy and cleaner emissions.

The result in the Grand Am SE is razor- sharp quickness.

Handling and ride: Top rate. It seems as though several auto makers are getting good at blending the hard sports feel with the softer "boulevard" ride. GM, at least with this car, is among them.

But some of the Grand Am SE's handling raves ought to go to Goodyear, the rubber company. Those Eagle GTs on the test model gave superb traction.

Head-turning quotient: Nice, except for that terribly proper rear end. The design is a crazy mixture of German autobahn and Detroit's inner-city Woodward Avenue. But it's slick, and it works.

Sound system: GM's Delco Series 2000. Excellent tonal quality and radio signal retention, AM and FM. Accurate, attractive and easy-to-use balance and fader controls. Excellent tape sound reproduction.

Mileage: Estimated 24 to the gallon, combined city-highway, running driver-only and with winter climate control system operating most of the time.

The Grand Am SE is equipped with a three- speed automatic transaxle. (The term "transaxle" refers to the axle and transmission arrangement in front-wheel-drive cars.)

Price-as-tested: $13,740, includes power door locks and windows, leather-wrapped steering wheel and parking brake handle, and the 3-liter V-6. The standard Grand Am engine is the more fuel-efficient, 2.5-liter, four- cylinder job.