2GR Misfire on a Lexus V6? Coil Symptoms and What to Replace
If you own a Lexus IS 350, GS 350, RC 350 or another car with the 2GR V6, there's a good chance you'll deal with a 2GR misfire at some point. The 2GR is a great engine, but coils are a wear item, and they live on top of a hot engine.
So let's walk through what a coil problem looks like, how to tell it apart from other causes, and what we'd replace.
Common symptoms
- Rough or shaky idle
- Stumbling or hesitation when you get on it
- Check engine light with a misfire code
- A flashing check engine light under load
- Fuel economy dropping without a clear reason
A flashing check engine light is the one to take seriously. Back off and get it looked at soon.
The biggest takeaway: diagnose before you buy
My concern is people seeing a misfire code and immediately ordering parts. Those same symptoms can come from spark plugs, injectors, a vacuum leak, or wiring.
Here's the simple test a good shop will do. Note which cylinder is misfiring, swap that coil with one from another cylinder, and see if the misfire follows the coil. If it moves, it's the coil. If it stays, look elsewhere. It's cheap, it's quick, and it keeps you from buying parts you don't need.
Replace one or all six?
We hear both sides. Replacing one is cheaper today and fixes the problem in front of you. Replacing the set means all six cylinders start from the same place, because all the coils have the same age and heat history. If one has failed, another may not be far behind.
If you plan to keep the car, doing the set usually makes sense. If you're about to sell it or budget is tight, replacing the bad one isn't crazy. Its really up to you.
On a V6, the rear bank coils can be harder to reach depending on the model. That's another reason people do them all at once. You only pay for that access once.
The HighSpark option
If you're replacing them anyway, this is a good spot to upgrade instead of just putting stock back in. HighSpark makes 2GR kits as boxes of three, so a V6 takes two boxes:
- HighSpark Ignition Coil for Toyota 2GR (Box of 3)
- HighSpark Ignition Coil Premium for Toyota 2GR (Box of 3)
Why HighSpark over stock coils? HighSpark rates the spark output at 2 to 2.5 times more powerful than an OEM coil, and they stabilize the voltage coming out of the coil, so the engine runs smoother and more stable. What you'll actually feel is throttle response. It's sharper. Now, I want to be honest here. This isn't a big horsepower part. Better combustion efficiency gets you a small gain in low-speed torque and horsepower, but it's minimal. The real win is response and a smoother-running engine.
So what's the difference between Standard and Premium? Standard is built for the street and the occasional track day. Premium is the track-focused tier, which HighSpark tunes to raise voltage starting at idle without giving up throttle response. Going by my own notes, that's about 25% better response and 7% less noise than Standard. Both are built the same way, with German copper wire and Kyocera resin. If it's a daily driver, Standard covers it. If it sees regular track days or you're adding power, that's where Premium starts to make sense.
There are several 2GR variants across Lexus and Toyota models. Don't order by engine name alone. Check the fitment on the product page, and if you're not sure, send your year, model and VIN to Tania or Kenia and they'll confirm before you order.
Do plugs at the same time
The coils have to come out to reach the plugs, so a lot of owners do both together. Check your maintenance records. If plugs are due or close, it's usually the smart move.
DIY or shop?
Front bank coils are approachable for a lot of owners. The rear bank can mean removing the intake plenum on some models, which is more involved. If you're not comfortable, have a shop do it. Either way, be gentle with old connectors. They get brittle with heat and age.
What we see most often
The most common call isn't a dead coil. It's a used car buyer who doesn't know the history and wants peace of mind. If the car has miles and you don't know when the coils were done, a fresh set is a reasonable baseline. You stop wondering about it.
The second most common is someone who has already done plugs and still has a misfire. That's where we slow down and ask whether the misfire follows the coil. Sometimes it's the coil. Sometimes it's an injector or a wiring issue, and new coils won't fix that.
And if you're an IS 350 owner thinking about looks too, the NOVEL carbon trunk spoiler is listed for the 2022+ IS 350 as well as the IS 500. For more on why HighSpark sells coils as matched sets, see our HighSpark matched kits post.
How to diagnose a 2GR misfire at home
You don't need a shop to take the first steps. A basic OBD2 scanner will tell you which cylinder is misfiring. Codes like P0301 through P0306 point to a specific cylinder, and a random misfire code points to something affecting more than one.
- Read the code and write down the cylinder.
- Swap the suspect coil with a coil from another cylinder on the same bank.
- Clear the code and drive the car the same way that caused the misfire.
- Read it again. If the misfire moved with the coil, it's the coil. If it stayed, look at the plug, injector or wiring for that cylinder.
That simple swap test saves a lot of people from buying parts they didn't need.
Install notes: front bank vs rear bank
One bank of a V6 is usually easier to reach than the other, and how much has to come off depends on the car. Take a look before you start. If you're comfortable with hand tools, this is a home job for many owners. If the back bank looks intimidating, a shop won't take long.
- Cool engine, battery disconnected.
- One coil at a time.
- Check plug wells for oil. Oil there is a valve cover gasket issue to fix too.
- Gap and torque new plugs to spec if you replace them.
When it's probably not the coil
If the misfire only happens cold, only at one RPM, or moves around between cylinders, keep an open mind. Worn plugs, a vacuum leak, or an injector can all look like a coil problem. A coil that's cracked, oil soaked or failing usually shows up as a misfire that stays on the same cylinder until you move the coil.
Year and model notes
The 2GR shows up in a lot of Toyota and Lexus models over many years. The Lexus cars we hear about most are the IS 350, GS 350 and RC 350. Don't assume your car uses a 2GR by name alone. The IS 250, for example, uses a 4GR. Check your engine code on the label under the hood or send us your VIN, and confirm fitment on the HighSpark product page before ordering.
Maintenance to prevent the next misfire
- Stay on top of spark plug intervals.
- Fix oil leaks into plug wells quickly.
- Keep the engine bay clean so you notice problems early.
- If one coil fails on a high mileage car, the others have the same age and heat cycles.
We explain why HighSpark sells coils as matched sets in our HighSpark matched kits post. If you have a V8 instead, our post on when to replace 2UR coils covers the same questions.
FAQ
How many HighSpark 2GR boxes do I need?
The 2GR kits are boxes of three, so a V6 takes two. Confirm on the product page.
Will new coils fix my misfire?
Only if the coil is the cause. Have a shop confirm the misfire follows the coil first.
Will HighSpark coils add horsepower?
Only a minimal amount of low-speed torque and horsepower from better combustion efficiency. The main benefits are sharper throttle response and a smoother engine.
Standard or Premium for a daily IS 350?
Standard covers a daily driver. Premium is the track-focused tier.
Who can confirm fitment?
Send your year, model and VIN to Tania or Kenia and they'll confirm.
What does a P0300 code mean on a 2GR?
It's a random or multiple cylinder misfire. That often points to something shared, like plugs due for replacement, fuel or a vacuum leak, rather than one coil.
Can I drive with a misfire?
We wouldn't push it. A steady misfire can damage the catalytic converter. Diagnose it soon.
Next step
If you're putting a plan together, the easiest thing is to add the parts you're looking at to your cart and hit Add to Quote. We'll look it over, confirm fitment and availability, and get back to you. If you'd rather talk it through first, reach out and Tania or Kenia can help with fitment and stock questions. No pressure at all. We'd rather you buy the right part once than the wrong part twice.
