This is a long story(but please bare with me). I bought my car about 6 months ago(1996 328is). The first day i bought it the water pump went out and my radiator blew up. Boy was I happy. I didn't know about the infamous plastic impeller, but now i do. Thats all fixed, but things went down hill from there. I really doubt i warped the head, but i just mentioned this to leave nothing out. Problems: I was pulling a good 29MPG driving to work everyday. One day the car started to misfire/hesitate. The check engine light comes on. Code says injector or ignition circuit was faulty. I replaced three injectors with brand new ones, and had the other three fully serviced/cleaned(dont ask why i did it this way). I reset the codes and it seemed to be ok for a while. I noticed the car was not performing so well anymore. It wasn't as smooth and loss of power, and my milage dropped about 4 mpg( this is all over some period of time, not all the sudden). Then it does the same thing, misfires check engine, same codes. I take it to a shop, they check the codes reset it and the car is "fine". I insist its not running like it used to, but he doesn't agree. I replaced the fuel filter, and presure regulator. After some time it does this again. I take it to the shop and same thing. After they reset the code it doesn't misfire anymore. Im out a few hundred dollars and am getting pissed. Again a few weeks later it does the same thing. I take it to another shop. He wants to replace two ignition coils for 400. Hmmm i think not, I bought two coils for 140 and did it myself. Few weeks later it does the same thing, but wait this time it gets worse. Im kicking out smoke like an old carburated 350. Im running rich like crazy. I run the car off, put the key in the on posistion and i hear some noise from the engine(its not running at this time). One of the injectors is being pulsed on (WTF?). I figured out which one it was and sure enough the plug for that cylinder was fouled. I swapped injectors, and still the same cylinder was giving me problems. I take it to a dealership now. They reset the code and say its fine. I looked at the bently manual electrical diagrams, and it shows that the injectors are controlled directly from the ECU(or whatever its called). but i dont buy it, i heard some buzzing noises besides the injector when it was being pulsed on for no reason. I would dyno my car to prove its not running right but im out of money and i cant find any competent mechanics. Right now its not misfiring but it sure is not up to par. I realy doubt its the ECU, and i guess i will never know because i will not pay 1000 or whatever it is for a new one. Any suggestions will help, at this point i have given up and am almost considering selling the car.