I’ll show you how to fix a p2187 System to lean at idle bank 1 on the VW Jetta , this also works on many other VW engines with a 1.8l or 2.0 l. The most common cause for p2187 or p0171 to set on this car is the PCV breather on top of the valve cover. it is very common for the PVC to start leaking vacuum and to set a system to lean bank 1 obd code. Other very common causes are the mass air flow sensor, rear main seal, and intake manifold. In this video, I will tell you what to look for when checking these engine components. We will be using a smoke machine to check the air intake system for vacuum leaks and using the scan tool to check the fuel trims after the repair is made to make sure this VW is fixed.