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: 700-R4 automatic transmissions may shift late or not upshift at all because of a stuck throttle valve inside the transmission. (1990-93)

Climate control: The temperature control lever may spontaneously slide from hot to cold, usually when the blower is on high speed. (1992-93)

Dashboard lights: The oil pressure gauge may read high, move erratically or not work because the oil pressure sensor is defective. (1990-93)

Engine knock: Engine knock on 4.3-liter engines during acceleration or climbing a grade is due to carbon buildup on the pistons. (1992)

Engine misfire: The EGR valve may stick open due to carbon deposits causing rough idle. (1994)

Hard starting: Engines with TBI may be hard to start after hot soak. (1990-93)

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.

1990-92 without air conditioning: Fan blades on 2.5-liter engine can break as a result of fatigue.

1991 S15/T15: Nut used to attach lower control arms, rear spring/shackle/shocks could "strip."

1991: Fuel tank sender seal may be out of position.

1991-93 4WD w/ABS: Increased stopping distances can occur during ABS stops while in 2WD mode.

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.

Three engines were available in the early '90s: a 94-horsepower, 2.5-liter 4-cylinder; 125-horsepower, 2.8-liter V6; or 4.3-liter V6, rated at 160 horsepower. By 1992, the 4-cylinder was developing 105 horsepower, and a high-output 4.3-liter V6 (standard on the GT) made 195 horsepower. Syclones got a turbocharged 4.3-liter V6, making 280 horsepower. Two-wheel-drive Sonomas had the 4-cylinder engine as standard and the 2.8-liter V6 as an option (except on the Special). The 4.3-liter V6 was standard on 4WD Sonomas, optional with 2WD. By 1993, GMC's "enhanced" 195-horsepower version of the 4.3-liter might be installed on all models except the Special and 2WD long-bed. (Chevrolet compact pickups could not have the "enhanced" engine.) A 5-speed manual transmission was standard with the 4-cylinder, 2.8-liter V6, and regular 4.3-liter V6. Four-speed overdrive automatic was optional (mandatory with the enhanced 4.3-liter), but not available with the 2.8-liter V6. Insta-Trac part-time 4WD had automatic-locking front hubs and shift-on-the-fly between 2WD and 4WD High. An electronic-shift transfer case was optional on all 4x4s with the 4.3 engine and automatic, except the Special.