P0174 code on OBDII reader

[NSXer]

folks

any help would be cool

23 1st edition v6 manual ... now covered around 12k miles

was on a road trip in Wales UK a couple of weeks ago and had a faulty o2 sensor (bank 2) and replaced by GRP - their Bosch one
Prior to that the car was running very rich and dumping a lot of fuel in. on removal of the o2 it was black and had soot deposits
This cleared the codes etc i was having. NB 1 sensor replaced, original on bank 1 remains

due to state of o2 sensor i was concerned with potential fouling ofr plugs as car appeared to have a slight misfire. changed all the plugs and replaced a couple of coil packs on those that had a bit of brown staining on the shaft.

With all that done, i done a hard reset on the ECU during the plug and coil service.

I now have a CEL with P0174 via my basic obd2 reader, the codes for o2 sensor, misfire etc have now gone. the car is going into reduced performance mode and i am at the end of my tether with this one.

Have got some advice to check for potnetial intake leak, blocked air filter (which i doubt as purcahsed and installed GRP blue one a couple of months ago) and the charcoal canister connections etc.

Any thoughts?

Modifications wise i have installed the following

Miltek v2 valve controller (its working as it should)
Miltek 3rd cat delete pipe
Miltek exhaust

Any help greatly appreciated in troubleshooting this code

 

[netsinah]

Perhaps you've seen all of the YouTube videos discussing code P0174. If not, here's one that provides an explanation of the code and suggests some causes that differ from the ones you've listed:



Or here's an automotive article which explains which "bank" of cylinders you're likely dealing with, on your V6 and also lists potential causes:

P0174 – Fuel trim. System too lean (bank 2) | OBDeleven

A P0174 diagnostic code indicates that the fuel trim system is too lean. Learn possible causes, symptoms, and troubleshooting tips for P0174.

obdeleven.com

And since you've got a Toyota 2GR-FE V6 engine (slightly modified), here's another YouTube video discussing that code, with that engine:



Because you were running too rich with the faulty O2 sensor, I wonder if you've got some clogged fuel injectors, but that's only one of the possible causes listed and I'm no mechanic. Or perhaps something went wrong, with the replacement O2 sensor, during installation?

Assuming you personally changed your plugs and some ignition coils, you've got some DIY skills and can likely explore some of the possible causes mentioned above, however unless you get lucky, you'll likely spend a fair bit of time/money figuring this out. For that reason, I'd suggest a visit to your dealer or "local/trusted automotive mechanic" to better pinpoint the issue. All that said, hopefully other Emira owners who've encountered this code, will provide more useful advice. Good luck resolving this quickly and post your solution, once known.