Background: 2007 Cooper base
86,000 miles

Recently purchased so don't know the history

Runs fine from start up until engine warms up

Idles rough and accelerates rough up to 3000 rpm then smoothes out

Mpg is excellent, around 40mpg (based on odometer and receipts)

I've gotton one code, P0302

I've read a lot on NAM about the rough idle/acceleration issue and everyone reports low mpg, but mine is high.

My uneducated logic says the whole system is running too lean, thus the high mpg and the misfire under acceleration. I have the Torque app but need some help with what to look at/ graph. Any help would be appreciated.

Thanks,

 

That code indicates a misfire. Specifically cylinder 2. Pull the plugs and look at them first. If they look ok then check the wires.

 

Thanks. Currently waiting for the spark plug socket to arrive in the mail. In the mean time the coolant system has sprung a leak. It looks like the pump or pump area. I have an appointment at a local shop in a few days and have ordered a pump in case it need replacing.