Fault code P2187 on Cosworth supercharged NC
 

I've got a 2006 NC with Cosworth supercharger. and I'm getting fault code P2187 System Too Lean at Idle (Bank 1).

http://www.obd-codes.com/p2187

I've had this fault code occasionally ever since I bought the car a year a go. No other fault codes.

However, it's now started to occur most days so is getting a bit annoying http://www.mx5nutz.com/forum/public/...efault/sad.png

Car runs great, just get a 'miss' every minute or so when idling; the idle suddenly drops but then catches itself.

The front O2 sensor was changed by the previous owner 18 months ago (in an attempt to fix this fault I would suspect). I've just changed the purge valve and solenoid as apparently these can cause this code.

Has anyone else had this fault code on their NC?

Do you have a wideband to see what is going on? Or any sort of datalongging system? If you are getting CEL codes, you must still have a stock ECU.

Thanks.

At the weekend I used the Torque Android App and a bluetooth OBD2 reader to get some freeze frame info when idling. It looks like I have Short Term Fuel Trim (STFT) of nearly 18% and Long Term Fuel Trim (LTFT) or over 20%. This seems high to me and possibly the cause of the fault code if the trims max out (25% each) before they can get the fueling rich enough,

Freeze frame information:
------------------
Fuel Status = 0 byte
Engine Load = 11.765 %
Engine Coolant Temperature = 83 °C
Fuel Trim Bank 1 Short Term = 17.969 %
Fuel Trim Bank 1 Long Term = 20.312 %
Intake Manifold Pressure = 4.206 psi
Engine RPM = 747 rpm
Speed (OBD) = 0 km/h
Timing Advance = 3.5 °
Intake Air Temperature = 45 °C
Mass Air Flow Rate = 1.59 g/s
Throttle Position(Manifold) = 10.588 %
Run time since engine start = 30 s
EGR Commanded = 0 %
Distance travelled since codes cleared = 9 km
Barometric pressure (from vehicle) = 14.794 psi
Catalyst Temperature (Bank 1,Sensor 1) = 404.6 °C
Voltage (Control Module) = 13.407 V
Engine Load(Absolute) = 12.157 %
Commanded Equivalence Ratio(lambda) = 0.998
Relative Throttle Position = 1.569 %
Absolute Throttle Position B = 10.588 %
Accelerator PedalPosition D = 31.373 %
Accelerator PedalPosition E = 20.784 %

find the vacuum/boost leak