I have a 1990 240 5 speed with 268k miles on it. Throwing a 2-3-2 lamda adjument code. I replaced coolant temp sensor. checked for vacuum leaks. replaced idle speed valve. cleaned throttle body. replaced fuel pressure regulator. o2 sensor was replaced a few months ago.Intake is in good condition and I also checked for leaks at the intake manifold. Car does not have a long crank or hard start up. No black smoke present upon startup. Can not drive car away till it warms up though. If I try to it just stalls out. I am left with only throttle position sensor,mass airflow, or a problem with the injectors as they are the only original parts remaining.I am about to loose my mind. Car runs almost fine otherwise just A funny hesitation on a decel accel transition. I pulled out the mass airflow meter today and it looks clean inside.Its terrible waiting every morning for it to warm up

 

check your RPM sensor too. surely you've put in a lot of fiscal resources...but hang in there, there's hope still.

make sure you check the wiring harness, it's connections at the sensors and all that. pull back the rubber boots and look for crimp failures.

 

Have you checked the Fuel Filter? Might be clogged.

 

Yea after throwing all the new stuff into it you might as well get the basics a new furel filter new air filter and spark plugs couldn't hurt anything.

 

Just did fuel filter,cap/rotor, plugs, and wires in the begining of the summer

 

if it is throwing a lamda code that implies the oxygen sensor is not working properly. You can measure the voltage from the sensor wire and you should see it vary from .1v to .9v (one tenth of a volt to 9 tenths of a volt) with the engine warmed up. If it is stuck or responds very slowly replace oxygen sensor.