I have searched the threads and never found an absolute fix on here. Some say MAP sensor, Some say Fuel pump, some say Fuel filter, Fuel rail, Fuel HPFS? My reader seems to not erase the old codes as one from my old code thrown P0597 for the thermostat is still there, but that's another story. I got a new code today which is P2187 Lean at idle! The car is running great, in fact it hasn't ran better, BUT, and I do say but, the idle is a bit irregular. The engine runs great on the highway ( I do 104 miles a day on open highway) but it seems to stumble a bit at idle and pulses or searches for idle a bit at stop lights. This is a BASE car and a daily driver and Iv'e got 117K on the clock now. I'm going to replace the fuel filter soon I have it on order. Maybe the fuel pump in the tank? but she never starves for fuel on the road, no limp mode as of yet, So I don't know where to lean towards. Any help/ suggestions from the group would be nice. PS sorry so long of a read,

 

Guys, I really need help. I have a state inspection due and will have to risk being cited by the police for not having inspection stickers on the car. Plus I don't want to keep throwing money at the car in parts that I really don't have. Thanks I'd really appreciate the help more than you know.

 

Well. After all my worry, the P2187 went away on it's own. The CEL went away but still remains logged in the system/ computer along with the thermostat P0597. I will attempt to go through state emissions and safety inspection tomorrow. Wish me luck!

 

Your whole lean problem could be caused by a faulty thermostat. The thermostat will change your fueling map depending on temperature.

The Coopers don't have a HPFP, so that isn't an issue.

Stumbly idles could be from low oil, worn spark plugs, incorrect engine timing (which is monitored intently, you would more than likely have a code for cam/crank correlation).

 

I recently had a similar problem with my BMW 328. I had idle issues, but it ran like a top on the highway. Fuel pump was replaced and the idle issues improved for about 2 months and then they were back. Monitoring the fuel pressure it was always in spec. Then one night it failed to start. It ended up being the fuel pressure regulator/filter in the tank.