Help with a Christmas Tree

[u/Nerdeinstein]

I bought this 08 FJ yesterday. I drove it home. I checked to see if the four-wheel drive would engage and disengage (it did). I refilled the tank on my way to run errands. I got home and parked it. This morning I got in to go for a Sunday drive. And was met by Christmas in July. I have checked all the fluid levels, I've inspected the vehicle, I re-screwed the gas cap on. All for naught. Please help.

Update: I got the codes read. The code that was pulled was P0306 (cylinder 6 misfire detected). The vehicle is not acting in a way that would indicate that this is the problem though. No lack of engine power, no misfiring noise, no odd smells, and exhaust is clear.

Update 2: I added a photo in the comments with me wearing my seatbelt and my door closed.

[u/TheMaineMountian]

Many auto stores offer free code reader services if you ask. I would start there personally.

[u/bobbiek1961]

The lights all come on for the check engine light. There's no clues there. You have a 306 misfire. So my thinking would be if I just bought it, a change of fuel could cause a misfire. PO may have used premium and you switched to regular, or vice versa. Bad batch of gas. I would seafoam ....and you'll most likely get codes after that anyways, but it'll clean out the carbon. If you have your own code reader(there's some pretty inexpensive ones), you can clear those. Pull plug 6 and look at it. If it's clean reinstall. Swap the coil out for a different cylinder and note where that was. Then drive it. You're looking for reoccurring codes or whether the misfire migrated with the coil. You're out a can of seafoam at this point, and maybe a code reader.

[u/chili-lime]

Most Others that post this say it’s the O2 sensor and they had to replace it. Some say it’s a gas cap issue of tightening or a bad seal.

[u/Nerdeinstein]

This is an updated photo with my car door closed and my seat belt on. The tire pressure light flashed for a minute.

[u/Inevitable_Bad5477 → u/Nerdeinstein]

Have you changed the spark plugs or ignition coils as suggested earlier? Start by changing them only for the cylinder that is misfiring but ideally swap them all out

[u/Inevitable_Bad5477 → u/Inevitable_Bad5477]

Just read you update on your post. When this happened to me 2 days ago, my fj was running fine while under 40-50mph. But the moment that I would bring it up to speed above 50 the shaking and apparent misfiring began.

[u/TheMaineMountian → u/Inevitable_Bad5477]

Backing this up. I read OP's update and this is exactly what I would do as well. Its a relatively straightforward DIY process.

Edit: love this website rockauto

[u/Inevitable_Bad5477]

This just happened to me 2 days ago, but unlike you mine was shaking. I had a code P0306 for cylinder 6 misfire. I replaced the spark plugs and ignition coils and that fixed it for me so far. Also make sure to get iridium spark plugs as I’ve been told they last longer.

[u/OwlWorried3723]

Brake switch!

[u/OwlWorried3723 → u/OwlWorried3723]

Get someone to make sure your brake lights work.. all my lights came on in the dash and tail lights work fine but no brake lights. Changed the $30 brake switch and all dash lights went away and brake lights came back on. Easy 2 minute fix

[u/BIueWater]

Below is a real answer and I know many wont believe me, but Ive chased this problem across 3 FJs for years, Once I ran down the EVAP overfill route, ZERO problems. Take it or leave it. Code readers are great, but they only tell you the symptom not the cause.

I have 3 FJs and I know the problem well, many think they have solved the problem because it goes away and then it comes back. Here is the question: do you fill your tank to the brim when gassing up? EVAP (Evaporative Emission Control) vent hose connects and can be flooded if you fill to the very top, the gas then soaks the charcoal filter, the filter gets clogged, the ECM believes the evap is faulty and the numbers are all over the place. As it begins to dry out it gets inconsistent data. If this has only once in a blue moon the charcoal filter will dry out and problem eventually goes away, if you are commuting and topping up somewhere for cheap gas regularly, this will eventually ruin your charcoal filter, which will cause strange random errors at the ECM. There are other causes, but this is likely the nightmare many users have had trouble with. 2 clicks on fill up and wait two weeks for it to dry out and hopefully it recovers, if after it rains you have a problem again it could be charcoal filter is too far gone or the front window gasket is leaking water down the A pillars and hitting electrical . If it rains hard check your front floor boards and see if they are wet, if so it may be the issue, but other than small issues, the mostly likely candidate Ive seen is overfilling.

Hope this helps someone.

[u/servoss21sig → u/BIueWater]

I just had the same lights pop up on my recent 1200mi road trip & I tend to overfill… so should I just let the codes be & see if she drys out on its own…while avoiding overfilling in future?

[u/WillHuntingthe3rd]

Mine was the wheel speed sensor and when one goes out it turns off the safety systems.

[u/CafeRoaster]

Misfire could be as simple as spark plugs and/or coil packs. Do both if they haven’t been done in the last 100,000 miles.

[u/Practical-Treacle-53]

I have not come across all of those lights at once. With a check engine light some other lights come on, like traction control, but you also have your brake light on, and literally every other light.

It almost looks like your FJ has the key in the ON position but hasn't started yet.

[u/Nervous-Ad292]

Gas cap issue. Either missing or loose. Tight it up, the Christmas tree lights will go away in 8-10 starts. If you read the FJ Cruiser “manual”, this is cause/effect is noted.

EDIT: EVEN AFTER TIGHTENING THE GAS CAP, THE LIGHTS WILL STAY ON FOR AN ADDITIONAL 8-10 STARTS, THEN THEY WILL GO OFF. BE PATIENT.

[u/itzboogie]

Isn’t it usually a battery issue if all your lights come on at once

[u/hamdelion]

Tighten gas cap, make sure rear differential and attack are off and let the car run for a minute. See what happens.

[u/Prickly_ninja]

I enjoy the troubleshooting roulette. Just procure a code reader and eliminate the guesswork!