Ive been having a problem with this since ive got my car. Its a 91 Si.
When it had the D16 in it the engine light would come on either when I was going down a steep hill, or slowing down ( gearing down or just braking ). I tried 2 different new O2 sensors and still had the problem.
I was told to change the fpr but I put the B16 in before I did that.
Fast forward, after I put the B16 in I didnt have that problem anymore, but I was using a chipped pr3 so it wasnt showing an O2 code. I changed to a stock ecu and its the same thing again. Slowing down or going down a hill the engine light comes on and gives me an 02 code. Ive tried 2 new 02 sensors and made sure that I had them wired correctly and I still get this problem.
Does anyone have any idea what is wrong with my car? It is really irking me that it seems unfixable. If my gas mileage wasnt so bad with the chipped ecu I would go back to it.