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Discussion Starter · #1 ·
Hello all
I have just joined this FJ forum, having owned 2 FJ's, the current being one of the last of the 2014 models.
Purchased new, it has ran flawlessly for 7 years, 50K miles, until now. All of a sudden, from running great yesterday, to the engine stumbling, shaking, not smooth at all today when started. Check engine light came on.
What changed? Getting a PO300 code, engine misfire, one of three codes on the scanner. Can't read the other 2 codes yet as I've not taken it out of the driveway.
Manual says to check like 10 categories, a hundred possibilities! But anyone know what is the MOST likely the cause of this sudden change in engine behavior? Nothing was done to it overnight to act up. Weather mild, gas cap tight, gas in tank, battery good, etc. What else to check, or do, before it goes to my very expert (and overpriced) mechanic?
Any help appreciated!
 

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Need the other codes. More than likely the misfire is a result of one of the other codes.

Sent from my SM-G781V using Tapatalk
 

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I’d look into changing the spark plugs. A set of OEM Densos cost $24 from Toyota and you can install them yourself in 30min. That’s a good place to start. Make sure you disconnect the battery to reset to ECU. I had a similar issue, but replacing the spark plugs did the trick for me. FYI, it’s over $4k for a knock sensor replacement if you take it to Toyota.
 

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Discussion Starter · #5 ·
Hello again
The FJ engine is running SO badly ( barely running) that it immediately stalls out in attempting to move it a few feet. Won't rev enough to move it just a car length. I can't get past the first code on the scanner because it is not drivable enough to retrieve the 2 other codes (he scanner tech guy I called said you have to drive if enough to obtain the other codes, to get past the first one).
Went from running perfectly to this condition overnight. I'm an older car guy with quite a bit of mechanic ability, but this has NEVER happened in another vehicle that I've owned- going from running perfectly to #!*% running the next day. Hard to believe that most all plugs or injectors went bad overnight. Tank is 1/2 full now, ran great after last fill-up (for half the tank).
I have had 2 fuel pumps go bad - one suddenly and one slowly - in my Chevy truck, but this was after 100K miles (plus) on the odometer. Is this a possibility with the (newer) FJ with 50k miles?
 

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Discussion Starter · #7 ·
Yes, possibly a rodent has chewed through something overnight, but nothing yet visible under the hood. Will keep looking there and elsewhere. No rodent issues on my other (4) vehicles, however. They all start and run as usual.
New info on my scanner after trying to move the vehicle: Codes 002,003,004 are showing up along with the PO300 (engine cylinder misfire codes).
Does anyone know if the 2014 FJ has a fuel pressure access port? I've heard the earlier models may have had these, something like a schrader valve somewhere on the fuel line. Toyota's later models may have omitted these, used fuel pressure sensors instead? Wouldn't a fuel pressure code show up (if low fuel pressure was causing all cylinders to misfire)?
 

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I'll 2nd the rodent damaged wiring hypothesis.

Little else except vandalism will cause the engine to go from running flawlessly at shutdown to barely running the next start after simply sitting overnight.

Spark plugs will be in perfect condition after only 50K miles on a '14 and are not likely a factor.

Rodent damage to ignition coil wiring and/or fuel injector wiring would be the first place I'd look.

There's no fuel pressure sensor on the 1GR-FE engine, so there will be no OBD code associated with fuel pressure. There's no fuel pressure test port either, you have to plumb a pressure measuring adapter into the existing fuel lines.

I assume you already had the fuel pump replaced under the Denso pump recall?

And why would you need to move the vehicle at all to read all the logged OBD codes?

(I've got a 2014 too, so I'm particularly interested in finding out exactly what's going on with your vehicle.)
 

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Discussion Starter · #9 ·
Dustin
Thanks for the heads up on the fuel pump recall- I had not heard. The dealership is no longer in business where I bought the FJ. No notice was sent to me on the recall of Jan15, 2020.
I have scheduled the fuel pump recall service with another Toyota dealer. Having it towed/serviced in a couple of weeks, should know something the first week of October. No evidence of rodents or tampering so far on the FJ.
 
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