2000 LC stalling, restarts fine

[gatormark91]

My 100 has a new problem stalling. Starts and idles fine. When you get up to highway speed, it will stall. It initially runs fine. Put it in neutral and it starts again, no problems. But it will be almost impossible to keep running, it will stall briefly and buck at all speeds. No codes set.

I had a new OEM fuel pump, tossed it in, no effect, same problem. No vac leaks, fuel trims are good, O2 sensor voltages are good, MAF value good, grounds are all perfect, battery is new, battery connections clean and tight. All coils are new. Wires near belt are good.

I am at a loss for this one. :-(

 

[AARONTLC]

My 100 has a new problem stalling. Starts and idles fine. When you get up to highway speed, it will stall. It initially runs fine. Put it in neutral and it starts again, no problems. But it will be almost impossible to keep running, it will stall briefly and buck at all speeds. No codes set.

I had a new OEM fuel pump, tossed it in, no effect, same problem. No vac leaks, fuel trims are good, O2 sensor voltages are good, MAF value good, grounds are all perfect, battery is new, battery connections clean and tight. All coils are new. Wires near belt are good.

I am at a loss for this one. :-(

Hmm. Just out of curiosity The Car Care Nut just posted a video on YouTube for a Sequoia with the 2UZ doing the exact same thing.

 

[Trapper50cal]

You already eliminated what I would have suggested...fuel pump. Maybe power to the pump is failing intermittently?

 

[nissanh]

Fuel filter?

 

[Trapper50cal]

Fuel filter?

I thought of that too...but I feel like that would present differently and get progressively worse
instead of causing stalls then restarting but it could be able to provide baseline fuel delivery
but not enough to keep running once the throttle is involved.

 

[87warrior]

Take another look at the MAF/MAF wiring circuit.

My 100 used to randomly stall. Replacing the MAF seemed to 'fix' it for awhile, then it would start randomly stalling again. I fought this for 5 years until it became undrivable when the RPM's started surging then stalling. I never could see an erroneous reading from the MAF using a Bluetooth dongle (OBDlink LX which is one of the fastest to read on the market). Even when using Techstream plugged into the OBD port the MAF readings were reasonable. It turned out that the pin on the MAF wire at the ECU was a bit loose. I unpinned the plug at the ECU and squeezed/tightened the pin on the MAF wire.

See this thread about the development of my issue: Low RPM surging and stalling - https://forum.ih8mud.com/threads/low-rpm-surging-and-stalling.1212451/

It hasn't stalled once since I tightened up the connection on the MAF pin at the ECU.

 

[gatormark91]

Fuel filter?

Yeah, ordered one for pickup this AM.

 

[gatormark91]

Yeah, ordered one for pickup this AM.

Ok, not the fuel filter. Going to clean the TB next.

 

[gatormark91]

So I can duplicate it now in my driveway. If I run the throttle up to about 3,000 RPM and hold it for there for a little bit, let it drop back down, settle down a bit. Then I turn the AC off, and turn the AC back on. When it gets the load from the AC it will stumble and die most times I do that. So when it's getting load at idle, the idle doesn't drop to the normal 750, the truck just stops.

 

[Trapper50cal]

Partially seized-up AC Pulley or condenser?

 

[gatormark91]

Watching the timing when it's doing it. Timing is at +-17 degrees at idle. There is a little roughness to the idle that it never had before lately. Turn the AC off, and it pulls timing back to 8. Stops at 8ish. Turn AC back on and the timing doesn't come back up. Watched it without messing with the AC, and it ran OK, then for no reason it pulled timing - 17, 15, 13... Stall.

So leaning towards maybe a crank or cam sensor going bad?

 

[gatormark91]

Update:

So I started looking on the Tundra 4.7 forums to see if anybody else had a problem with a 2UZ engine like I was having.

And I came across one guy who had the exact same symptoms that I was having. And he ended up figuring out that it was...

... a bad tank of gas.

I put a bottle of HEET gas drier tank, and, to my surprise, that resolved it.

This is the first time in my life I've ever had to deal with that, I've never had a bad tank of gas before!

But all good, that fuel pump was well past its service life anyway.

Thanks all!