Very strange: hot weather and sudden rough running, no power, major shuddering

[cgreer00]

Any ideas about what I could be looking at here? 2006 LX with 208K on it. New plugs and coils about 15K miles ago, also new radiator. Has always run VERY well. I was in heavy traffic yesterday and it was about 100 degrees outside. It was fine and the A/C was cold and there were no apparent issues. No overheating or missing and the idle was smooth. Had about 3/4 a tank of new gas in it. Pulled in to the hotel and shut it off. The valet asked me to move it to a different spot so I started it back up about 10 seconds after shutting it off and it immediately was running like crap. Very rough idle, like it was barely able to run. NO power at all, pressing the accelerator did next to nothing. I put it in drive and it just barely crept over to the spot. I shut it off and wondered if it was going to need to be towed. We got everything out of the truck and then the valet started it back up and it ran perfectly fine...no issues at all. This was after sitting for about 5 minutes. Since then it has been totally fine. No CEL has come on at all either.

Of course now I am worried about it having issues again in hot weather and me being somewhere remote when it happens. What are your thoughts on this? I drove it for an hour back home today and it was totally fine, ran smooth as silk.

 

[Eicca]

Tough to nail down exactly without a code, but I had similar intermittent crappy running symptoms on my old Lexus that didn’t throw a code, and it turned out to be VVTi solenoids going bad (I found out when one failed outright the night before a road trip).

If you haven’t done them already, they take like 30 seconds to swap and would be good to do preventively at that mileage as they’re one of those things that could leave you stranded.

 

[cgreer00]

Tough to nail down exactly without a code, but I had similar intermittent crappy running symptoms on my old Lexus that didn’t throw a code, and it turned out to be VVTi solenoids going bad (I found out when one failed outright the night before a road trip).

If you haven’t done them already, they take like 30 seconds to swap and would be good to do preventively at that mileage as they’re one of those things that could leave you stranded.

Is that something that would be evident at idle? Or only at higher revs?

 

[Eicca]

Is that something that would be evident at idle? Or only at higher revs?

Idle for sure, the VVTi system requires the most phaser actuation at idle so that the higher revs are kept safe in the event of VVTi malfunction.

TechStream even has a test where you can manually shut down a VVTi solenoid at idle and watch it run like garbage.

 

[cgreer00]

Idle for sure, the VVTi system requires the most phaser actuation at idle so that the higher revs are kept safe in the event of VVTi malfunction.

TechStream even has a test where you can manually shut down a VVTi solenoid at idle and watch it run like garbage.

Ok that's good to know. It's just so strange how it went from perfect to awful, and then back to perfect, all within a 10 minute span.

 

[Trunk Monkey]

Never seen a post here about vvti solenoids going bad, not common at all. You can check for a stored code with a reader. I would lean towards something with the evap system, charcoal canister and fuel with it being hot.

 

[newbielx470]

If your fuel pump is still original, that could be the cause. Usually happens on a hot day or after running uphill for prolonged period, make a stop, and when restarting, truck runs very rough and even stalls after a few seconds. Then after waiting for a few minutes everything is good again.

 

[cgreer00]

That is kind of what I was thinking, but my gas tank was almost totally full. I always thought that vapor or charcoal canister issues with the 100 series was when the tank was much more empty.

 

[cgreer00]

If your fuel pump is still original, that could be the cause. Usually happens on a hot day or after running uphill for prolonged period, make a stop, and when restarting, truck runs very rough and even stalls after a few seconds. Then after waiting for a few minutes everything is good again.

Good thought. It could very well be original. Is there any way to test this or should I just have it replaced?

 

[newbielx470]

Good thought. It could very well be original. Is there any way to test this or should I just have it replaced?

Not sure if there is a way to test. Probably just need to replace it. There was an older thread about this issue and great details on how to replace it DIY (the fuel pump is under the rear seat).


This thread was on how to replace it:

Thank You Toyota! ...Fuel Pump Replacement.

Fuel pump started 'whining' last week, so its time to pluck the original out and replace it. Unlike the Starter on my LX470....the fuel pump is actually easy to replace. You do NOT have to drop the fuel tank in order to do this repair. Most folks know there is an 'access panel' under the...

forum.ih8mud.com

 

[xeuxaz]

Tough to nail down exactly without a code, but I had similar intermittent crappy running symptoms on my old Lexus that didn’t throw a code, and it turned out to be VVTi solenoids going bad (I found out when one failed outright the night before a road trip).

If you haven’t done them already, they take like 30 seconds to swap and would be good to do preventively at that mileage as they’re one of those things that could leave you stranded.

What was your mileage at the time of failure? Did the engine see regular oil changes?

 

[Eicca]

What was your mileage at the time of failure? Did the engine see regular oil changes?

Mine failed around 200k. I personally changed it regularly but I can’t speak for the previous owners. I’ve seen reports of those VVTi solenoids failing as early as 120k. Worth replacing preventively at 200k anyway.

 

[Eicca]

Ok that's good to know. It's just so strange how it went from perfect to awful, and then back to perfect, all within a 10 minute span.

That’s about how mine behaved. It would start, run fine, suddenly run like crap for a bit, then be fine again for another few weeks/months until it died outright.