Hello. I am having a problem with my 89 190E 2.6. I just rebuilt the head and did a valve job on it because it ran like crap. Turns out one of the valves had a big gouge in it. Its all back together and runs and idles perfect. Although the check engine light will flicker on and off and sometimes stay on. When it does this, the engine will die sometimes (if at a red light persay) or when driving, totally lose power. It just all around runs horrible and seems bogged down. when the check engine light goes off, the motor instantly runs normal. I am suspecting the O2 sensor. I had a computer from an 86 300E and I put it in to see what would happen and it runs fine with it in. The check engine light never comes on (unless I unplug the O2 sensor) and seems to run fine. My only complaint with this computer is that sometimes briefly the car will hesitate for a bit. The mixture has been recently adjusted. I really dont know what to do. Should I try a new O2 sensor and replace the original computer? Or do you not think that is suspect. What is the difference between the 2 computers. Thanks for any help.

-Andy