Hopefully others will chime in cuz I don't see where the OP gave an update for his fix and yours seems similar.
I have no idea at this point just some ideas.

Sounds like you have fuel delivery- unless ECM is shutting everything down but would be nice to throw codes.
Did you remove the fuel rail for any reason?
When it stalls are your plugs wet?
Battery fully charged?

The engine ground located at EE(in pic above) is a very important one- it is a ground for ECM and the ignition coils, etc, and the noise shield for knock sensors, etc.
Also, might wanna ohm engine ground points EE & ED(pic above) to negative battery termal(battery unhooked) to verify ground path.
PS- Might also be good to do a quick inspection for crack/defects in IG2 Fuse(Ignition) located in fuse box interior and pull and re-seat ignition relay in engine bay because I'm starting to wonder if your problems have been all electrical since the first code was thrown. Out of ideas at this point.
Hope this helps.

 

Thanks Margate330 for all your help.

Tried to restart her again this morning and the same thing, starts fine then just stalls after a few seconds. Scanned her again and no codes whatsoever!!!

I did not remove the fuel rail. Not sure if the new plugs are wet as I haven't pulled them to check after trying to restart. The old ones were a little wet, but I don't know how long they were on there as I recently purchased the car (about 10K ago). Everything has been running great until the recent snafu with the VSC light and sensor/ coil fault code at cylinder 5. I'll probably take a look at the new plugs this evening when I get home.

I double checked both the engine grounds you suggested to look at. Both were on tight, but I'll look at them again.

Another thread I found online seemed promising. It offered a solution for a similar stalling issue after disconnecting battery/ replacing plugs/ coil packs on a ES 350. The solution revolved around checking/reseting the security system as it could be killing the engine. I don't know enough about the Lexus security system but I suppose I can try to do that. Ever heard of this?

Another thread I found said to check the key ignition switch at the steering wheel as it may be going out and turning the car off as a safety precaution. But wouldn't that throw a code? I don't know.

I will take a look at the fuses again, but they all checked out previously (even the ones under the driver side dash). I also suspected a weak battery, but this one is an interstate 24F under warranty through Oct 2020. Still I'm running out of options here so that may very well be the culprit.

There is a breather hose that connects from the topside of the back of the engine block, runs under the plenum and connects to the air box flex pipe that can probably be replaced. But not sure this would be making it stall? I'm going to be swapping out the PCV valve this evening, just cause it's easy and cheap to do (it would be great if this is all it is!!).

I'm also thinking I can try swapping out MAF on the air box. But again am a bit hesitant because no fault codes are being detected. Would a faulty MAF throw a code (I know it would make it stall)?

Thanks again for you help.

 

Try to start it again
When it dies out, check your immobilizer/security light. (center display area)
If the light is out, its not an immobilizer issue.
If the light is flashing or ON, there is a communication drop.

Let us know what the condition after doing this test.

 

Thanks for the idea Nad1370-

I replaced the PCV valve then did the test you described to check the immobilizer/security.

Tried to start her and she stalled in the exact same way— turned on for a few seconds then stalled. The light was not on nor flashing during the start or after she stalled.

I have a new MAF sensor (Denso MAF Sensor 22204-31020) being delivered today and will report back after I install it and try to start her again.

In the meantime, if you or anyone else has any other ideas/suggestions, please let me know. However for anyone that is just finding this thread now, please be sure to read through previous posts as a lot of information has already been covered and I don't want to clutter the thread with posts referring to previous posts. Thank you.

Much respect!

 

I reached out to OP via a private message and luckily they got back to me.

They said the original problem was an easy fix— they forgot to reconnect the fuel pump harness during re-installation. They said they would send a picture but the car was not presently in their possession.

Can anyone provide location so I can double check?? I feel like I already did this but at this point my brain and memory is like spaghetti.

 

Energizing signal from ECM to fuel pump Relay is located at "wire to wire connector junction(plug)" located at EB2 in the drawing above.

 

Im kicking my @$$ for this.
I vaguely remember these systems has a Fuel pump resistor in them.
If you leave it unplugged, you will experience whats you have now.
Dont ask me how i came across it but....find this FP resistor (pics i supplied should be straight forward)
Make sure this 2 wire BLACK connector is plugged in.
Im hoping its just this simple for your issue.

 

If so that would explain the fuel smell and stalling after start with no codes at this point.

The Fuel Pump Relay is de-energized at engine cranking up so it runs full speed via voltage thru the C/Open and then Relay turns ON at engine idle to route voltage thru fuel pump resistor to lower the pump output - if resistor unhooked will cut the fuel completely. And the connector at EB2 will do it too- either one will cut fuel at idle but allow fuel to start.. Has to be.

 

Holy ****!!! That was it!!!!

A million miles of thanks to you my friend!!! As well as to Margate330 for hanging in there with me and providing all the info.

That must have been what the OP was talking about.

I kept overlooking that unplugged harness on that fuse/relay box because there was no where to plug it into. In my state of worry and without any logical explanation for why it was stalling, I reasoned that the harness was some sort of plug for testing and it completely slipped my mind that I had unplugged something from there. I kept focusing on the darn spark plugs/ coil packs, and the vacuum hoses, the electrical harnesses, etc.

The fuel pump resistor was still attached to the metal tray, which was on the other side of the garage out of site. Probably would have eventually figured it out once I started putting it all back together but it didn't cross my mind to look there because I forgot about it and was focusing on getting the plugs/ coil packs/ sensor replaced. Then was thrown for a loop with the codes.

Was ready to concede I needed to tow her to the mechanic. Probably would have figured it out once the tray went back in but I'm so stubborn I would have kept digging around in there for a few more days, maybe weeks.

I even plugged the wiper motor back in to its harness thinking it may need to be plugged in to start.

Again, a million miles of thank you!

Much respect!

 

Im banking a case of Modelo on this, Phil.

Im guessing the OP had to take the cowl off to do the plugs and Cam sensor.
I think this FP resistor is bolted to the cowl.
So either disconnect the connector or unbolt it off.
The OP probably forgot to plug it back in.

im really digging your diagrams. 👍

 

The fuel pump resistor is indeed bolted to the cowel/ tray. I'd gladly send you and Margate330 a case of Modelo each. If you guys are interested PM your mailing address and I'll get it there via amazon

 

^^^^
Hahaha.
No worries man.
Pass this info forward if any of the members here have the same issue.
Glad everything worked out for you.

Now you can have a beer or two after this ordeal.
Cheers. 🍻

 

Too late already having a cold one now. lol

It's nice that you followed up with the fix and shared with us all.
Cheers!