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What P0300 means for your Tundra
On the Toyota Tundra, P0300 typically comes from ignition coil-on-plug failure or worn iridium spark plugs on the 5.7L 3UR-FE V8 (and 4.6L 1UR-FE V8). All 8 cylinders use individual coils, and the rear cylinders near the firewall (4, 6, 8) fail first from heat. The 5.7L plug service interval is 120k miles but real-world fouling starts around 90k, especially on trucks that idle a lot or tow regularly. Less commonly, the 2007-2009 Tundra 5.7L was the subject of a camshaft/lifter tick TSB that can present as a misfire after long idling.
Top 3 Toyota Tundra-Specific Causes of P0300
40%
#1 CAUSE
Rear-Bank Ignition Coil Failure
The 3UR-FE 5.7L V8 uses one coil-on-plug per cylinder. Coils on the rear bank cylinders 4, 6, and 8 see the worst underhood heat and fail at 80k-150k miles. Swap a suspect coil with a known-good front-bank coil and rescan - the misfire will move with the coil. OE Denso coils $50-90 each; sets of 8 aftermarket coils $150-260.
Parts
$50-$90 ea
Labor
$30-$100
Total
$80-$200
30%
#2 CAUSE
Worn Iridium Spark Plugs
Toyota spec is Denso FK20HR11 iridium with a 120k-mile interval, but in real-world Tundra duty (towing, idling, off-road) plugs degrade by 90k. All 8 plugs must be replaced together. Labor is moderate because of the V8 layout - upper intake plenum removal helps access on the rear bank.
Parts
$80-$140
Labor
$120-$300
Total
$200-$440
15%
#3 CAUSE
Cam/Lifter Tick (Early 5.7L 3UR-FE)
Some 2007-2009 5.7L Tundras experienced a known cold-start cam-follower tick that, when severe, can cause partial valve-lift loss and intermittent misfires. Toyota TSB T-SB-0035-11 addressed this with cam-follower replacement. If the truck has a top-end tick at cold start and throws P0300, ask the shop to check follower wear before assuming plug/coil.
Service
$600-$1500
Parts
$200-$400
Total
$800-$1900
Note: remaining percentage covers low compression, vacuum leaks, MAF issues, and fuel pressure. Hands-on diagnosis required for those.
Most Affected Tundra Model Years
| Year | Engine | Primary Cause | Typical Mileage | Notes |
|---|---|---|---|---|
| 2007-2009 | 5.7L 3UR-FE V8 | Coils + cam-follower TSB | 80k-150k | TSB T-SB-0035-11 cam follower replacement applied to some VINs |
| 2010-2021 | 5.7L 3UR-FE V8 | Coils + plugs (rear bank) | 90k-150k | Most common P0300 source on modern Tundras |
| 2007-2019 | 4.6L 1UR-FE V8 | Coils + plugs | 90k-150k | Same coil failure pattern, less torque load |
| 2007-2014 | 4.0L 1GR-FE V6 | Coils, plugs, EGR | 80k-140k | Shared with Tacoma - rear bank coils first |
Is It Safe to Drive Your Tundra with P0300?
Short answer: Limit driving and fix it within a week. Unlike P0420, P0300 actively damages other components every mile. Unburned fuel destroys the catalytic converter in weeks. If the check engine light is flashing (not just on), stop driving immediately - that signals active misfire severe enough to damage the converter in real time.
How to Diagnose P0300 on a Toyota Tundra
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Pull freeze-frame data and check service history. Most OBD-II scanners (under $30) show RPM, coolant temp, and load at the moment the code set. If your Tundra has 80k+ miles and the plugs have never been replaced, start there.
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Swap-test coils to find a failing unit. If new plugs do not resolve the misfire, identify which cylinder fired the freeze-frame, swap that coil to another cylinder, and rescan. A coil that follows the misfire is your problem.
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Check for companion codes. P0300 with P0171 (lean) usually points to a fuel or air metering issue. P0300 with P0011/P0021 (cam timing) suggests timing chain or VVT solenoid. Always fix the root cause - misfires from lean conditions or bad cam timing will return.
Want a step-by-step diagnosis tuned to your Tundra's year and mileage? Run a $5.99 AI diagnosis report - includes cost breakdown and a printable mechanic summary.
Toyota Tundra P0300 - Frequently Asked Questions
Why does my Toyota Tundra throw P0300 after towing?
High load and heat accelerate coil breakdown on the 3UR-FE. If the misfire only shows up during or after heavy tow miles, the rear-bank coils are the prime suspect. Have them load-tested or swap-test them at the next service.
What does the 2007-2009 Tundra 5.7L cam follower TSB say?
TSB T-SB-0035-11 covers cold-start tick and intermittent valvetrain noise that can progress to misfires. The remedy was new cam followers under warranty for affected VIN ranges. Outside warranty, repair is $800-$1,900 depending on shop.
How much does it cost to fix P0300 on a Tundra 5.7L?
Single coil + plug set: $150-$300. Full 8 coils + 8 plugs: $500-$900 installed. Cam follower TSB repair (rare): $800-$1,900. AI diagnosis report at /diagnose will pin down which to do first.
Is a P0300 misfire safe to drive in a Tundra?
Light driving is okay - severe misfires (especially flashing CEL) will destroy the 5.7L catalytic converters which run $1,200-$2,200 per side to replace. Fix within 1-2 weeks of code setting.