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1) So I am having an issue with my 2010 GX460 where the 4LO indicator is blinking, and the check engine light and slip are also on. I have never shifted out of 4HI, so I know for certain it's not in 4LO and hasn't been in many years.
2) When I check my engine codes I got a P0304 - Cylinder 4 Misfire Detected.
3) Idles fine, but when I shift to R or D, it becomes rough.
4) However, if I reset the code, it idles fine and the roughness completely goes away and I can drive it like nothing ever happened. (Until I let it sit, turn it back on and all the lights come back on).
What are some things a novice that is willing to get dirty could check in this situation? Could this be an ECM issue possibly?
Last edited by alfreema; 06-03-23 at 05:41 AM.
Reason: Removing FIXED from title, because it wasn't fixed.
A lot of times that code is thrown when one of the coil packs fails. Not sure what your mileage is and how old your spark plugs are, but you could try that first. Cylinder 4 is near the front so access should be easy.
Spot on. I pulled the #4 coil and #2 coil. Ohm meter showed consistent values across blades 1 and 4 and a couple other blades. Pulled the #4 spark plug and it was a little wet but also sorta charcoalish. Put in new plug in #4 (and #2 since I was that far along). Swapped the #4 and #2 coils just in case the spark plug wasn't the problem. Reset the code and so far the problem has not come back. So looks like it was the spark plug (fingers crossed!)
I’m having the same problem. If you don’t mind me asking- how many miles does yours have on it?
Originally Posted by alfreema
Spot on. I pulled the #4 coil and #2 coil. Ohm meter showed consistent values across blades 1 and 4 and a couple other blades. Pulled the #4 spark plug and it was a little wet but also sorta charcoalish. Put in new plug in #4 (and #2 since I was that far along). Swapped the #4 and #2 coils just in case the spark plug wasn't the problem. Reset the code and so far the problem has not come back. So looks like it was the spark plug (fingers crossed!)
I’m having the same problem. If you don’t mind me asking- how many miles does yours have on it?
Not at all. It's at 176,000 miles.
If you have the exact same problem with a p0304 code, I can say that the #4 and #2 coils and plugs (toward the front of the car and the passenger side) are quite easy to get to. #6 and #8 (also on the passenger side, but to the rear of the engine) look a lot more complicated to get to.
My strategy was to pull those coils and then swap them to see if the problem followed the coil, then I would know it was a coil. But when I pulled them, I put an ohm meter across the outside blades and they were almost identical. Same with a couple other blades, so I was quite sure it wasn't a coil problem. I went ahead and swapped the plugs for both since I had the coils out and then I _did_ swap the coils just in case the problem wasn't resolved with the spark plugs.
But the plug was obviously a likely culprit when I pulled it:
Hi. i have the same problem with my 2012 Lexus gx460. is there anyone finded the solution?
Mine ended up being a blown head gasket (ouch -- ended up being $6500 repair!). There are several things to check before jumping to that conclusion though. I'd have a certified Lexus technician check it out if possible.
Hey Guys,
Having a similar problem with my 2014 GX. A little bit of context: The engine in my vehicle is not the original engine. It's a very long story, but basically a shop completely destroyed mine while doing a routine oil change. They admitted fault and payed for everything, but this is a used engine that they put in. The good news is that mine was around 70k miles and this new engine is roughly 55k. That said, in 2 months of having this engine in the vehicle, I've had to replace 2 coils (I think #5 and #3). Does this seem normal/reasonable at 55k miles? At this point I'm pretty concerned about where this engine came from and what kind of history it has. I've never had to replace a coil in my life (maybe im lucky) and now 2 in 2 months seems like something is off. Trying to figure out if there is a larger issue going on here
Hey Guys,
Having a similar problem with my 2014 GX. A little bit of context: The engine in my vehicle is not the original engine. It's a very long story, but basically a shop completely destroyed mine while doing a routine oil change. They admitted fault and payed for everything, but this is a used engine that they put in. The good news is that mine was around 70k miles and this new engine is roughly 55k. That said, in 2 months of having this engine in the vehicle, I've had to replace 2 coils (I think #5 and #3). Does this seem normal/reasonable at 55k miles? At this point I'm pretty concerned about where this engine came from and what kind of history it has. I've never had to replace a coil in my life (maybe im lucky) and now 2 in 2 months seems like something is off. Trying to figure out if there is a larger issue going on here
Is it throwing codes?
In your situation my gut tells me they pulled an engine out of a wrecked vehicle and then overhauled it with inexpensive aftermarket stuff to keep their costs down. Do you know what brand of coils they were, when they were removed? If you just have aftermarket coils and plugs with a short life then there's probably nothing more sinister going on, though it's painful to have to keep replacing them as they fail. Maybe next time a coil goes out, get them to swap the entire bank with OEM (Denso?) coils and Denso plugs.
It looks like they used NGK GP Platinum Plugs when they put the new engine in. I assume the new coil was also NGK when they put it in. The second round is actually still happening, so haven't spoken to them about what is going in it now. (I've learned all of this today and the shop is closed. Calling them tomorrow.) Should NGK work in it? It says compatible, but I've seen mixed reviews. Should we use OEM instead? (Apologies for any incorrect terminology, in way over my head here.)
4Lo and Check Engine Lights after fuel pump replacement
I found this thread doing a search online. I’m having the exact same issue. I had a fuel pump put in because they told me that’s why my car died a few days ago while driving it. The fuel pump was put in on Saturday and two days later I get into my car for the first time and now these lights are on and the 4LO is flashing. Could this be related to a job gone wrong? Thank you for any insight, you all may have! 4LO also flashing but didnt get captured when I took this.
Originally Posted by alfreema
Symptoms:
1) So I am having an issue with my 2010 GX460 where the 4LO indicator is blinking, and the check engine light and slip are also on. I have never shifted out of 4HI, so I know for certain it's not in 4LO and hasn't been in many years.
2) When I check my engine codes I got a P0304 - Cylinder 4 Misfire Detected.
3) Idles fine, but when I shift to R or D, it becomes rough.
4) However, if I reset the code, it idles fine and the roughness completely goes away and I can drive it like nothing ever happened. (Until I let it sit, turn it back on and all the lights come back on).
What are some things a novice that is willing to get dirty could check in this situation? Could this be an ECM issue possibly?
05-24-23, 07:06 AM
2010 GX460 blinking 4LO + Check Engine + Slip w/ p0304
Still getting a p0304 so the problem did not follow the coil, which I swapped with #2.
