The plot thickens....it seems the engine will only stall if I let it be in fuel cut off mode (aka not spraying fuel on a coast down). This ONLY happens after the car has been driven once during the day. For example this evening I drove home after letting my car sit for 8 hours at a friend's house.....as soon as I push in the clutch while it's in fuel cut off mode BAM stall. But if I don't let it be in fuel cut off, it will never stall. Interestingly enough on the way there it didn't exhibit this condition. Makes a guy wonder.....

It's pointing to something fuel related. Since the only components left are fuel pump and regulator....guess what's happening next.

 

This might be a long shot but have you checked your crankshaft end play?

 

I have not physically checked the endplay but I did check the vtec solenoid for debris....nothing there. If it got this bad you'd figure it would be littered with metal if that's what it was.

 

It's easy to do so I would check it either way, your symptoms are really weird.

 

Checked the end play, .006-.007" seems good to go, checked it multiple times. Thank goodness.


Fuel pump on ze way.

 

My car did this same thing for a long time, eventually replacing the MAP sensor + o-ring with a new o-ring and a used eBay MAP sensor appears to have fixed the problem for me. I also have the Karcepts unit, K&N FIPK, etc.

When you were testing for vac leaks using the propane torch how were you detecting vacuum leaks? I just went through a similar issue (minus stalling) with my IS300. Codes for slow o2 response on both cylinder banks, lean. Tried o2 sensors, didn't fix the issue. Tried leak testing it by ear like how I used to do it on older cars and was unable to find anything. It wasn't until I ran logging with STFT live that I was able to figure anything out. I found a dryrotted valve cover port gasket that dropped a full 13% of STFT at idle once fixed that I was completely unable to detect by the usual engine note changing. Car popped the codes again the next day so I got the logger out and found that the STFT popped when I was stopped, which made me realize that the brake booster was leaking under vacuum.

 

I did the ol cigar smoke test yesterday, no leaks. I've replaced the MAP once already....unless I've gotten really unlucky. Lol. Thanks for the response though man!! I'll update it...I do have a 3rd MAP sensor.

 

No change with fuel pump + regulator.....disconnected the EVAP circuit which SEEMED to help....but then returned to stalling and high fuel trims not that far in the future.

Going to pull the valve cover and replace that gasket + check valve clearance again. At the end of my rope guys.

 

What injectors did you replace the originals with?

 

Good set of used OEM injectors. There was no change in anything with these.