2000 INFINITI I30

Typical onset: 90,000-150,000 mi

Symptoms: Harsh 2-3 or 3-4 shifts, especially when cold, Slipping in 3rd or 4th gear under load, Delayed engagement from Park to Drive, Metallic debris in fluid, burnt ATF smell

Fix: This 4-speed auto is known for wearing clutch packs and valve body bore erosion. Band-aid fixes (fluid flush, solenoid swap) rarely last. Full rebuild runs 12-16 hours labor, or R&R with used/reman unit at 8-10 hours. Many shops won't touch rebuilds anymore—easier to swap.

Estimated cost: $2,200-3,800

Typical onset: 120,000-180,000 mi

Symptoms: Rattling from front of engine on cold start (first 3-5 seconds), Check Engine Light with cam/crank correlation codes (P0340, P0335), Gradual loss of power, rough idle, If chain jumps timing: catastrophic valve-to-piston contact

Fix: VQ30DE uses plastic-backed guides that disintegrate. When they fail, the chain slaps and can jump teeth, bending valves. Preventive replacement is 8-10 hours: timing cover removal, water pump while you're in there, all guides, tensioners, chain. This is an interference engine—if it jumps, you're looking at head work or replacement.

Estimated cost: $1,400-2,200

Typical onset: 80,000-140,000 mi

Symptoms: CEL with P1140, P0340, or P0345 codes, Rough idle, hesitation on acceleration, Poor fuel economy, sluggish throttle response, No-start or extended crank if crank position sensor fails

Fix: The variable valve timing solenoids clog with sludge or fail electrically; camshaft position sensors crack internally. Solenoids are 1.5-2 hours (buried under intake plenum). Crank sensor is easier at 0.8-1.2 hours. If you've got sludge, expect repeat failures unless you address oil change history.

Estimated cost: $300-650

Typical onset: 70,000-120,000 mi

Symptoms: High or erratic idle (1,200-1,800 RPM), Stalling at stoplights after highway driving, Surging idle when A/C compressor cycles, Poor cold-start idle quality

Fix: The IACV and throttle body collect carbon deposits. Most techs try cleaning first (throttle body cleaner, 0.5 hours), but if the valve motor is worn, replacement is needed at 1.2-1.5 hours. Not a safety issue, just annoying. Cleaning buys time but rarely permanent.

Estimated cost: $180-450

Typical onset: 100,000-150,000 mi

Symptoms: Clunking on hard acceleration or deceleration, Excessive engine movement visible from engine bay, Vibration through floorboard at idle in Drive, Shifter shudder when shifting into Reverse

Fix: The hydraulic front mount fails, allowing the V6 to rock excessively. Replacement is straightforward but requires supporting the engine: 1.5-2.5 hours. OEM mounts last longer than cheap aftermarket; don't skimp here or you'll be back in a year.

Estimated cost: $250-450

Typical onset: 100,000+ mi

Symptoms: Coolant odor in cabin, especially with heat on, Visible coolant weeping from rear of engine (passenger side), Slow coolant loss, no external puddles, Steam from engine bay after shutdown

Fix: The rear freeze plugs (behind the engine, firewall side) corrode and weep. Crossover tubes crack at welds. Both require significant disassembly—intake manifold, throttle body, sometimes exhaust work. Rear freeze plugs are 6-9 hours; crossover tube is 4-6 hours. Not a fun job in a transverse V6.

Estimated cost: $600-1,400