Tl* the contact owns a 2005 Toyota runner. The contact stated that the check engine light was illuminated. The vehicle was taken to the dealer where the contact was advised that the air induction pump failed. In addition, the contact stated that the secondary air injection switch was also damaged as a result of the air induction pump failure. The air induction pump was replaced but the failure…
2005 Toyota 4Runner engine problems
moderate 22 complaints filed with NHTSA · avg repair $3,100 · see engine across all vehicles →
Failure mileage
Complaints
22
Recalls
0
Avg fix
$3,100
1fire
When does it fail?
Of the 22 engine complaints filed for the 2005 Toyota 4Runner, here's the actual mileage breakdown — failures cluster heaviest at 75,000-100,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
What stands out
Of the 5 model years of Toyota 4Runner we track for engine problems, this one carries the most owner complaints on file — 22.
No new NHTSA engine complaint has been filed on this vehicle in over 14 years — the issue may be aging out of the active population.
The failure pattern owners describe
Buyer takeaway: The 2005 4Runner's V8 engine has a well-documented secondary air injection system defect that triggers dangerous limp mode, plus a recurring head gasket problem around 100K miles. Expect potential repair costs of $2,000–$5,000 and be aware that Toyota has not recalled these issues for the 4Runner despite covering the same failures in other models.
The 2005 4Runner's 4.7L V8 and 3.0L V6 engines show a pattern of distinct problems. The secondary air injection system is the most common complaint: owners report the check engine light illuminating with diagnostic codes P0418, P1441, P1444, and P2440, triggering limp mode that cuts vehicle speed to unsafe levels (20 mph on highways). Some say the air induction pump and switching valves fail; others report the relay or solenoid sticks. Repair costs run $2,000–$3,000, and owners note Toyota covers the same engine fault in Tundras and Sequoias but not 4Runners.
Head gasket failure appears around 100,000–170,000 miles. Owners report coolant leaking into cylinders (especially cylinder 6), confirmed by borescope inspection, causing rough starts, white smoke, check engine lights, and overheating. Repairs cost $2,500–$5,000. One owner reports the radiator boiling over without warning.
Exhaust manifold leaks allow fumes into the cabin, described as a rotten-egg sulfur smell. One dealer blamed New England fuel sulfur content; others cite faulty manifold design. A TSB exists but dealer claims some engines fall outside coverage.
High idle problems are reported when the air-conditioning compressor engages—RPM swings between 750 and 1500, making the vehicle lurch forward even while stopped. Owners describe difficulty holding the brake and dangerous creep speeds. Toyota claimed this is normal operation.
One complaint describes sudden full-throttle engine revving while stopped, attributed to electronic throttle control software glitch.
Same Toyota 4Runner engine reports on nearby years: 2006
Failure modes owners describe
Secondary Air Injection System Failure (Relay/Pump/Valve)
The secondary air injection system relay, air induction pump, switching valves, or solenoid fails, triggering check engine light and limp mode that severely restricts engine output.
When: 90,000–172,000 miles
Symptoms owners cite: Check engine light and VSC/TRAC lights illuminated; Vehicle enters limp mode with maximum speed reduced to ~20 mph; Unsafe for highway driving; Loss of power
Codes mentioned: P0418, P1441, P1444, P2440
Repairs/costs cited: Air induction pump replacement; secondary air injection switch or relay replacement; switching valves and exhaust manifold replacement. Costs cited: $2,000–$3,000.
Recalls/TSBs owners mention: Toyota covers the same fault in Tundras and Sequoias but does not recall or assist 4Runner owners. Some dealers told owners "there were no recalls" and offered no further assistance.
Head Gasket Failure
Head gasket deteriorates and leaks coolant into the combustion chamber, causing overheating, rough idle, and engine damage.
When: 100,000–170,000+ miles
Symptoms owners cite: Engine losing coolant; Coolant visible in exhaust or entering cylinders; Rough engine start lasting 15 seconds; White smoke from exhaust; Check engine light (P0306 misfire on cylinder 6 commonly reported); Radiator boiling over without warning; Dashboard warning lights illuminated
Codes mentioned: P0306
Repairs/costs cited: Head gasket replacement. Cylinder 6 is a known failure point. Costs cited: $2,500–$5,000.
Recalls/TSBs owners mention: Toyota previously identified limited vehicles for recall. Owners outside those parameters state Toyota denies responsibility. One owner researched the database and found ongoing failures beyond recalled vehicles.
Exhaust Manifold Leak (Rotten Egg Odor)
Exhaust manifold cracks or seals fail, allowing exhaust fumes (sulfur smell) to escape into the cabin, especially when rear window is open or recirculate air is on.
When: Not specified; affects multiple model years from 2003–2006
Symptoms owners cite: Rotten egg or sulfur smell in cabin; Smell strongest when reaching 3,000–5,000 RPM; Exhaust odor pulled into cabin when rear window open and recirculate on; Smell reported as "horrible" and causing nausea
Repairs/costs cited: Exhaust manifold replacement. Cost cited: $2,500.
Recalls/TSBs owners mention: TSBs exist for 2003–2006 model 4Runners on this issue. One dealer stated the contact's engine was not covered under TSB. One manufacturer response attributed odor to high-sulfur fuel in New England.
High Idle RPM and Unwanted Forward Creep
Engine idles excessively high (750–1500 RPM), especially when air-conditioning compressor engages. Vehicle lurches forward while stopped, requiring excessive brake pressure to hold. Owner reports vehicle can idle at 25 mph on flat surface and retain 55 mph when accelerator is released at highway speed.
When: Not specified
Symptoms owners cite: Idle RPM fluctuates between 750 and 1100, or reaches 1500 RPM; Vehicle moves forward while stopped and parked; Difficulty modulating brake at high idle; Abnormal brake pressure required to keep vehicle stationary; Vehicle idles at 25 mph on flat surface, 45 mph on slope; Vehicle retains speed on highway deceleration
Repairs/costs cited: Not specified; Toyota told owners "this is normal."
Recalls/TSBs owners mention: Toyota claims high idle and creep behavior is normal operation and declined to address it.
Electronic Throttle Control Malfunction
Electronic throttle control circuit or software glitch causes sudden unintended full-throttle acceleration while vehicle is stationary with foot on brake.
When: Occurred twice in approximately 2 years
Symptoms owners cite: Engine suddenly revved to full throttle while stopped with foot on brake; Rear tires squealed; Condition persisted after restart until engine was shut off and restarted again after 10 seconds
Repairs/costs cited: Not specified; issue resolved after restart delay.
Oil Leak from Cylinder 6
Oil leakage from cylinder 6 requiring valve job.
When: 182,505 miles
Symptoms owners cite: Oil leak in cylinder 6
Repairs/costs cited: Valve job required.
Synthesized from 22 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 1 most recent
Had engine trouble with your 2005 Toyota 4Runner?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the engine problem on the 2005 Toyota 4Runner?
It's a documented issue but not catastrophic. 22 complaints have been filed. Repairs average $3,100 and most owners catch it before it causes a breakdown.
At what mileage does the engine typically fail?
Across the 15 complaints that reported odometer mileage, most engine failures cluster between 80,000 and 150,000 miles, with the median around 110,000. A quarter of owners report trouble before 80,000; a quarter make it past 150,000. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to engine?
No active recalls currently cover engine issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2005/Toyota/4Runner.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.