1991 OLDSMOBILE BRAVADA

Typical onset: 120,000-180,000 mi

Symptoms: Excessive oil consumption (more than 1 qt per 1,000 mi), Metallic knocking from crankcase, especially cold start, Low oil pressure at idle when fully warmed, Blue smoke on deceleration or startup

Fix: These 4.3L engines are known for piston skirt scuffing and rod/main bearing wear due to marginal oiling and lean factory tune. Requires complete lower-end rebuild or short block replacement. Expect 18-24 labor hours for removal, rebuild, and reinstall with all gaskets and seals.

Estimated cost: $2,800-4,500

Typical onset: 100,000-150,000 mi

Symptoms: Slipping between 1st and 2nd gear under load, No 3rd or 4th gear (stuck in 2nd), Delayed engagement into Drive or Reverse, Burnt transmission fluid smell, dark brown or black fluid

Fix: The 700R4 four-speed automatic is the weak link in these trucks. Sun shell failures, 3-4 clutch pack burnout, and valve body issues are typical. Most need a full rebuild with updated parts. Figure 10-14 hours labor plus a quality rebuild kit and torque converter. External cooler lines also prone to leaking at crimps.

Estimated cost: $1,800-3,200

Typical onset: 80,000-140,000 mi

Symptoms: SERVICE 4WD or SERVICE AWD light on dash, Grinding or clicking from transfer case area, AWD system not engaging (stuck in 2WD), Intermittent engagement, especially in cold weather

Fix: The electronic encoder motor that shifts the transfer case planetary gears fails from moisture intrusion and worn brushes. Thermal actuator seals also leak. Encoder replacement requires dropping the transfer case skid plate and accessing the rear output. 3-5 hours labor, though some techs do it from underneath without full case removal.

Estimated cost: $400-900

Typical onset: 90,000-150,000 mi

Symptoms: Stalling when fuel tank below 1/4 tank, Hard starting after sitting, requires extended cranking, Fuel gauge erratic or pegged at empty/full, Engine stumbles or cuts out during acceleration

Fix: In-tank fuel pump and sender assembly corrodes and fails. Requires dropping the 27-gallon fuel tank (had a recall for filler neck cracking). Replace pump, strainer, and sender unit as assembly. 2.5-4 hours labor depending on rust and whether you need to fight fuel tank strap bolts.

Estimated cost: $450-750

Typical onset: 100,000-160,000 mi

Symptoms: Rich fuel smell in cabin or under hood, Hard starting when engine hot (vapor lock), Rough idle and hesitation, especially when warm, Fuel pressure drops rapidly after engine shut-off

Fix: The CMFI spider injector sits under the intake plenum and feeds individual poppet nozzles. Fuel lines crack and leak internally, causing drivability issues. Requires upper intake manifold removal and complete spider assembly replacement. 4-6 hours labor with new plenum gaskets and updated nozzle style.

Estimated cost: $600-1,100

Typical onset: 100,000-160,000 mi

Symptoms: Clunking from front end during turns, especially parking lot speed, Vibration at highway speed that changes with throttle input, Clicking or popping when turning at low speed, Grease leaking from CV boot or differential seals

Fix: The independent front suspension uses CV axles that wear at the inner and outer joints. Front diff carrier bearings also wear from constant torque in AWD mode. CV axle replacement is 2-3 hours per side. Front diff rebuild or carrier replacement adds 6-8 hours with fluid and seals.

Estimated cost: $350-650 per axle, $800-1,400 for differential work

Typical onset: 80,000-120,000 mi

Symptoms: ABS light on, pump runs continuously or not at all, Hard brake pedal with poor stopping power, Brake pedal pulsation even during non-ABS stops, Pump motor cycling constantly when key is on

Fix: The Teves Mark II ABS system uses a hydraulic pump and nitrogen-charged accumulator. Pump motors burn out, accumulators lose pressure. System still has regular braking when failed, just no ABS. Pump/accumulator replacement is 3-4 hours, bleeding the system requires special procedure. Many owners delete and go manual brakes.

Estimated cost: $650-1,200