Each vehicle report contains one rating chart for representative model. Consumer Guide® rates in ten key areas: Performance, Fuel Economy, Ride Comfort, Steering and Handling, Interior Noise, Controls and Materials, Driver Room, Passenger Room, Cargo Capacity, and Insurance Costs. These ratings compare the particular vehicle rated to ALL other vehicles, not a vehicle's standing in a particular class. In the ratings table, "1" is the lowest rating and "10" is the highest rating.

Consumer Guide's® Auto Editors have scoured repair bulletins and questioned mechanics to search for commonly occurring problems for a particular vehicle. In some cases we also give possible manufacturer-suggested solutions. In many instances these trouble spots are Technical Service Bulletins posted by the manufacturer, however, we have our own expert looking at additional vehicle problems.

Automatic transmission: 4T60E transmissions may drop out of drive while cruising; shift erratically; or have no second, third, or fourth gear because of a bad ground connection for the shift solenoids. (1991-94)

Automatic transmission: TH-125 or 440-T4 automatic transmissions may shift late or not upshift at all. The problem is a stuck throttle valve inside the transmission. (1990-94)

Engine noise: A tick or rattle when the engine is started cold may be due to too much wrist-pin-to-piston clearance. (1994-95)

Engine noise: A rattling noise from the engine when the car is started after sitting is often caused by automatic-transmission pump starvation or a sticking pressure-regulator valve. (1991-95)

Steering noise: The upper bearing mount in the steering column can get loose and cause a clicking, requiring a new bearing spring and turn-signal cancel cam. (1994-96)

Transaxle leak: The right front-axle seal at the automatic transaxle is prone to leak. GM issued a revised seal to correct the problem. (1992-94)

Valve cover leaks: The plastic valve covers on the 3.1-liter engine were prone to leaks and should be replaced with redesigned aluminum valve covers. (1994-95)

This table lists costs of likely repairs for comparison with other vehicles. The dollar amount includes the cost of the part(s) and labor (based on $50 per hour) for the typical repair without extras or add-ons. Like the pricing information, replacement costs can vary widely depending on region. Expect charges at a new-car dealership to be slightly higher.

1990 w/Kelsey-Hayes steel wheels: Cracks may develop in wheel mounting surface.

1990: Stoplamps may not illuminate.

1990-91 in 15 states: Due to corrosion of front engine cradle bolts, where road-salt usage is heavy, steering shaft could separate from steering gear.

1991 coupe: Fog lamps and low- and high-beam headlamps can be operated simultaneously on some cars, causing circuit breaker to overload and trip.

1991: Front-door shoulder-belt guide loops may be cracked.

1992: Reverse servo pin of 4-speed automatic transmission may bind.

1993: Manual recliner mechanisms on some front seats will not latch under certain conditions, causing seatback to recline without prior warning.

1994-95: Wiper/washer may operate intermittently, or not at all.

1995: Center rear-seatbelt anchor plate could fracture in a crash.

1995: Seatbelt anchor can fracture in crash.

This chart details a range of prices in year-by-year listings for vehicles in three condition levels:

Good: a clean low-mileage, solid-running vehicle that needs little or no repair.

Average: a car with normal miles on the odometer, perhaps a few scrapes or dings; engine might need a minor repair or two, but runs acceptably well.

Poor: might have potentially dangerous problems with the engine and/or body, or abnormally high mileage; definitely in need of mechanical attention. Valuations reflect wholesale prices paid by dealers at auction, and retail prices on used-car lots. Each range covers all trim levels and engine types for a vehicle with a typical amount of equipment--usually an automatic transmission, air conditioning, stereo, etc. Fully loaded vehicles may cost more. Average mileage is 12,000 miles per year. Keep in mind that these are guidelines only. Actual selling prices vary- especially from region to region.

Powering the base Grand Prix LE model in 1990 is a 2.3-liter 4-cylinder Quad 4, while a 3.1-liter V6 comes standard on SE and STE models. The V6 can also be ordered for the LE. The Quad 4 provides 160 horsepower at 6200 rpm and 155 pound-feet of torque at 5200 rpm. The normally aspirated V6 delivers 140 horsepower at 4800 rpm and 180 pound-feet of torque at 3600 rpm. A turbocharged version of the V6 is standard on the Turbo Grand Prix Coupe, optional for the STE sedan. The turbo engine cranks out 205 horsepower at 4800 rpm and 220 pound-feet of torque at 3200 rpm. The turbocharged V6 is replaced in '91 with a brand-new 3.4-liter, double-overhead-cam, 24-valve V6, and comes standard on the new GTP model. This engine delivers 210 horsepower at 5000 rpm with a 5-speed manual, 200 horsepower with GM's new electronically controlled 4-speed automatic. Torque is rated at 215 pound-feet at 4000 rpm. The new engine is an available option on all other Grand Prixs, except the LE sedan. Beginning in '92, the 3.1-liter V6 becomes the standard engine, replacing the 2.3-liter 4-cylinder Quad 4. For '93, a new 4-speed automatic transmission is available for the base 3.1-liter V6 as well. For '94, the base engine remains a 3.1-liter V6, but the entirely new design produces 20 more horsepower than the previous engine, with 160 horsepower at 5200 rpm and 185 pound-feet of torque at 4000 rpm. Also the optional twin-cam 3.4-liter V6 is upgraded in '94 to produce 210 horsepower with the 4-speed automatic, the same as when equipped with the 5-speed manual--dropped for '94--making the 4-speed automatic the only available gearbox, as the aging 3-speed automatic is also eliminated as member of the powertrain team.