My 85 535i has developed an irregular miss on one cylinder (I think) It occurs after start up, only once it is on the oxygen sensor and pretty much goes away if I put my foot in it. It's almost like lean surge only worse. O2 sensor reading are normal, maybe swinging a little bit more than usual, perhaps not though. I tried checking the exhaust manifold temps with a temp gun but didn't find anything. Anything else besides just an injector problem? I've got spares, but I don't know which one is giving me problems. A couple of bottles of Techron? Mike W.