My service engine light doesn't come on all the time, but when it does, it reads code 45 everytime. I have replaced the O2 sensor but it didn't help the surging problem i'm having. it is also running rich. I have tried adjusting my TPS and the timing but that didnt seem to help either. Could it be a bad coil? Previously, I replaced the MAF, fuel filter, distibutor & module, one of the injectors, O2 sensor, and the ECM. Does anyone have any suggestions? Thanks!