fault coad 0A emmision (lambda) control

[jdbmw325is]

my car is reading 0A as a fault coad. is the (lambda) control a sensor? or could it be a buntch of things dealing with emmisions.

Symptoms: sometimes my car will start right up. other times it will turn for quite a while and then finally start. it will run alittle rough but then smooth out after it heats up. Also if I’m driving the car seems to run fine but if I’m stopped at a light the check engine light will pop on.. if I rev the engine a bit it will go away.

[accident]

lambda is 02 sensor

[jlevie]

That fault code essentially means that what the DME perceives as the A/F ratio is out of range. That can be the result of intakes, a fuel system or injector problem, a bad AFM, an aged O2 sensor, misfires, etc.

The place to start is to have a smoke test run on the intake and fix any leaks. Run the fuel system tests in the Bentley and repair as indicated. The useful life of an O2 sensor is not more than 100k. So if that applies, replace the sensor. If that fails to fix the problem you'll have to move on to less common causes.

[txtorquemade]

Geesh, now MY 87 325is is running like crap. It was just running a bit rough, hard to start occasionally, no power, wont even redline. In third or 4th gear.

NOW its got a horrendous rattle under the car. Cant tell is it the transmission or the cat conv. It started subtle but now it wont hardly idle, is not even driveable.

Sorry for threadjacking....I know I hate that, but this is exactly what mine was doing before the horrible noise began under the car.

Cat conv and or O2 sensor .... IM thinking. Any help???

[evil_twin]

clean the o2 sensor. it's worth a try. the cat will only give problems if it's clogged.

[txtorquemade]

Im thinking it IS clogged though... how can I tell...anyone?

[jlevie]

Have a back pressure test run to find out if the catalytic converter is plugged up.

[evil_twin]

or... unbolt the cat from the headers, and run the car. see if the car runs any better.