Engine stalled mid drive, engine bay whistle, then 420 code. (1 Viewer)

[JayDee]

hi mud, I could use some advice. 07 LX470, 190k. I've had the truck for 3 years and 20k miles. No major issues until a few weeks ago.

Was driving over a mountain pass and noticed that when I accelerated, there was a high pitched whistle from engine bay. Letting off the gas slightly caused the whistle to stop. On the downhill side of the pass, the engine started to idle rough and then I lost all power. Slowed it down and got safely to side of road. Checked fluids and temps, all gauges looked normal. Started it up, no CEL and kept driving. The next day (120 miles later) CEL + VSC TRAC lights came on. OBD says its a P0420, driver side bank.

I talked to my local Toyota mechanic about O2 sensors & cats and he suggested testing for exhaust leaks. Local muffler specialist checked it out and said no noticeable leaks, although I hear a "tick" periodically, even after warmed up. He suggested replacing the cat and that driving it was OK, even with the 420 code.

I drove into the mountains again on Thursday and on another mountain pass (this time going uphill) engine stalled and I coasted to a stop, this time, no shoulder at all. Outside temps high 80s, AC on. It took about 40 minutes to get it started: electric and starter were going, but engine would n't catch, kind of like when you run out of gas. could be a fuel system issue? I got it started and turned around, as I didn't want to have bigger issues way out in the boonies.

I've read a bunch of posts about these various issues and have a list of preventative maintenance to do since I am unsure about the history:
- spark plugs (perhaps backing out?)
- throttle body cleaning (if super dirty, could it run too lean/rich?)
- MAF sensor cleaning (couldn't hurt?)

Can a bad/clogged cat cause loss of power? Other suggestions?
Thanks in advance for pointing me in a direction. Also, I have an OBD reader, but not tech stream.
JD

 

[JayDee]

Anyone experienced this before?

 

[JerrySM]

Mystery problems are a pain... Have you read through this post yet?

P0420 Code Solved, insights gained

Posting this in case it helps somebody else down the line. I've been chasing down an intermittent P0420 code since I purchased my 05 a couple months ago. Thinking maybe this was the last straw that caused the PO to trade it in which is fine by me. There are a whole bunch of threads on this...

forum.ih8mud.com

 

[Mike NXP]

Anyone experienced this before?

I've seen other post with similar symptoms and it ended up being the fuel pump but it's a guessing game. Doesn't seem like the outside air temp was hot enough to cause a fuel boiling / tank issue.


I don't think plugs or clogged cat is your issue and I would focus more on fuel and air. Seems like it happens when the vehicle is hot and under a load, then after cooling down it's good to go again?

Some easy first steps
Check air filter
Clean MAF
Check vac lines under the hood

Start thinking about swapping fuel pump.

How many miles on your truck?

When it runs, does it run good or do you have other issues? Plenty of power when hitting the throttle? If so, that is a good sign that it's not your spark plugs or exhaust system and the problem is more intermittent like fuel delivery .

Engine needs spark, air, fuel, and compression. Assuming you got plenty of compression and spark, focus on air and fuel.

 

[krispykritter]

Any chance it got too warm heading up the pass? I came east over I70 yesterday and saw coolant temps climb into the low 230s on the uphills outside Vail and Silverthorne - I had to let off the gas and cruise up under 55 mph to keep from overheating. OAT was like low 80s.

I'm glad I've had torque pro up during my highway drives lately because I'm not sure I would've noticed the temp gauge climbing as early as I did without the big coolant temp gauge on my phone.

Also, fuel boiling will cause the non-start issue but I've never had my 100 shut off from it - it just refuses to start again once shut off.

 

[jerryb]

If you rely on the testing the exhaust people did, and without techstream, I'd lean to quality of fuel.

Originally I was thinking air injection whistle at the exhaust header. They could whistle up top to.

First thing I'd do is fill completely full with the most expensive fuel I could find.

ODB reader fuel trims / misfire count second.


temp gun on the fuel rail, above 160F it might die regardless of any other condition.
If fuel trims around +30, suspect air in the rail- doesn't explain a whistle though.

 

[jerryb]

you know. My wife car whistles. It's the plastic cover underneath.

Separate issues I think

 

[JayDee]

Mystery problems are a pain... Have you read through this post yet?

P0420 Code Solved, insights gained

Posting this in case it helps somebody else down the line. I've been chasing down an intermittent P0420 code since I purchased my 05 a couple months ago. Thinking maybe this was the last straw that caused the PO to trade it in which is fine by me. There are a whole bunch of threads on this...

forum.ih8mud.com

Thanks for that! Looks like I need to connect with techstream

 

[JayDee]

I've seen other post with similar symptoms and it ended up being the fuel pump but it's a guessing game. Doesn't seem like the outside air temp was hot enough to cause a fuel boiling / tank issue.


I don't think plugs or clogged cat is your issue and I would focus more on fuel and air. Seems like it happens when the vehicle is hot and under a load, then after cooling down it's good to go again?

Some easy first steps
Check air filter
Clean MAF
Check vac lines under the hood

Start thinking about swapping fuel pump.

How many miles on your truck?

When it runs, does it run good or do you have other issues? Plenty of power when hitting the throttle? If so, that is a good sign that it's not your spark plugs or exhaust system and the problem is more intermittent like fuel delivery .

Engine needs spark, air, fuel, and compression. Assuming you got plenty of compression and spark, focus on air and fuel.

Air filter is newish, replaced at 185k, truck now at 190k. Will check MAF and vac lines. I was wondering about fuel pump.

The truck did feel sluggish, but at the time I wrote it off to lots of wind resistance, altitude and a full load.

 

[JayDee]

If you rely on the testing the exhaust people did, and without techstream, I'd lean to quality of fuel.

Originally I was thinking air injection whistle at the exhaust header. They could whistle up top to.

First thing I'd do is fill completely full with the most expensive fuel I could find.

ODB reader fuel trims / misfire count second.


temp gun on the fuel rail, above 160F it might die regardless of any other condition.
If fuel trims around +30, suspect air in the rail- doesn't explain a whistle though.

Looks like techstream is next. I run high quality 91 all the time so hopefully this is not the culprit. Will probably replace fuel filter while I'm at it…. at least get the easy, inexpensive items done first to rule them out.

 

[JayDee]

Any chance it got too warm heading up the pass? I came east over I70 yesterday and saw coolant temps climb into the low 230s on the uphills outside Vail and Silverthorne - I had to let off the gas and cruise up under 55 mph to keep from overheating. OAT was like low 80s.

I'm glad I've had torque pro up during my highway drives lately because I'm not sure I would've noticed the temp gauge climbing as early as I did without the big coolant temp gauge on my phone.

Also, fuel boiling will cause the non-start issue but I've never had my 100 shut off from it - it just refuses to start again once shut off.

It was warm for sure but nothing crazy. I don’t have torque pro- does that connect via a Bluetooth ODB connection?

 

[krispykritter]

It was warm for sure but nothing crazy. I don’t have torque pro- does that connect via a Bluetooth ODB connection?

Yeah, it's a common android app for keeping an eye on whatever is available over an obd2 connection. Works with most cheapo obd/Bluetooth adapters.

I only ask about the temps since I saw mine climbing rather alarmingly doing similar mountain passes. Probably not the issue.

 

[JayDee]

This weekend I replaced spark plugs. Two on the right bank came out with very little pressure. On the left bank, one of the coils was filthy. I pulled it and the spark plug was barely in there. There was also a crack running the length of the coil, probably from high pressure blowing past the plug.

Thanks to @2001LC for the post about plugs backing out. Great info.

Replaced all plugs with Denso Iridium TT and got a Toyota Denso coil from the local dealer. While I was in there, I cleaned the MAF Sensor and Throttle body. Both were in good shape.

First test drive the truck felt way better. I didn’t realize how sluggish it had gotten. The “tick” noise is gone during idle, although I still hear some noise after driving coming from somewhere in the exhaust, like when things get hot and start cooling off.

Now, will drive locally for a while and see if I get another P0420 code.

Thanks for the input!

Above are two coils. Left is what most of them looked like. The right is after wiping it down, note the longitudinal crack in the middle.

 

[krispykritter]

Two on the right bank came out with very little pressure. On the left bank, one of the coils was filthy. I pulled it and the spark plug was barely in there.

I had this exact same issue, and also did the job after seeing 2001LC's post about it being common.