The 1987 Firebird is a solid third-gen F-body with typical GM throttle body injection issues and transmission weaknesses. The 2.8L V6 and 305 V8 are robust if maintained, but automatic transmissions (TH700-R4) are glass jaws, and cooling system neglect kills engines.
TH700-R4 Automatic Transmission Failure
Common · high severityTypical onset: 80,000-140,000 mi
Symptoms: Slipping on 3-4 upshift or delayed engagement, No overdrive or stuck in third gear, Burnt fluid smell, metal shavings on dipstick, Shuddering during light throttle acceleration
Fix: Complete rebuild with upgraded clutch packs and valve body modifications. 12-16 labor hours. External cooler lines and cooler often need replacement simultaneously due to debris contamination.
Estimated cost: $1,800-3,200
Throttle Body Injection System Failures
Common · medium severityTypical onset: 60,000-120,000 mi
Symptoms: Hard starting when hot, long cranking, Rough idle, stalling at stop signs, Hesitation on acceleration, surging at highway speed, Check Engine light with codes 33, 34, 44, or 45
Fix: TBI injector replacement, throttle position sensor, IAC valve, or fuel pressure regulator. Diagnosis 1-2 hours, repairs range 2-4 hours depending on component. Fuel filter clogs frequently—replace first.
Estimated cost: $350-900
Intake Manifold Gasket Failure (V6 and V8)
Common · medium severityTypical onset: 70,000-110,000 mi
Symptoms: Coolant loss with no visible external leaks, White smoke on cold start that clears, Rough idle, misfires on specific cylinders, Coolant in oil (milky dipstick) in severe cases
Fix: Intake manifold removal, gasket set replacement, resurface if warped. 6-8 hours labor. On 2.8L V6, lower intake gaskets rot from coolant crossover design. Mandatory to replace coolant while open.
Estimated cost: $650-1,200
Rear Main Seal and Oil Pan Gasket Leaks
Occasional · low severityTypical onset: 90,000-150,000 mi
Symptoms: Oil spot under rear of engine after parking, Oil accumulation on bellhousing or transmission case, Low oil level between changes, no visible drips up front, Oil-soaked clutch (manual trans) causing slip
Fix: Rear main seal requires transmission removal: 8-10 hours on V8s, 6-8 on I4/V6. Oil pan gasket is 3-4 hours but often done together. Two-piece rear main design is prone to leakage as rope seal deteriorates.
Estimated cost: $800-1,600
Distributor and Ignition Module Failures
Occasional · high severitySymptoms: Sudden no-start, no spark condition, Stalling when engine reaches operating temperature, Intermittent dying while driving, restarts when cool, Tachometer dropping to zero while running
Fix: HEI ignition module mounted inside distributor fails from heat. Module replacement 1 hour, but distributor cap, rotor, and coil often need simultaneous replacement. Heat-sink compound critical for module longevity.
Estimated cost: $250-500
T-Top Weatherstrip and Structural Leaks
Common · low severitySymptoms: Water dripping on seats or headliner during rain, Musty smell, wet carpet on passenger side, Wind noise at highway speeds from T-tops, Popping or creaking sounds over bumps (body flex)
Fix: Weatherstrip replacement 2-3 hours per side. Drain tubes under T-top channels clog with debris—cleaning these costs nothing but prevents water intrusion. Body flex is inherent; subframe connectors help but are 4-6 hour install.
Estimated cost: $400-700
Fuel Pump Failure (In-Tank Electric)
Occasional · high severityTypical onset: 80,000-130,000 mi
Symptoms: Stalling after 15-20 minutes of driving, Loss of power under load, hesitation uphill, No start with whining or silent fuel pump, Engine dies when fuel level drops below 1/4 tank
Fix: In-tank pump requires dropping fuel tank: 3-4 hours labor. Strainer sock often clogged with rust from old tanks. Sending unit commonly replaced simultaneously. Running tank below 1/4 kills pumps prematurely.
Estimated cost: $450-750
Buy one with service records showing recent transmission work and cooling system maintenance; avoid high-mileage automatics without rebuild documentation, but mechanically sound examples are affordable, fun drivers.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.