Ok. Now something weird is going on. My check engine light has been on due to me using only one o2 sensor which is normal. But now my speedometer isnt working right. It moves when car is just idle'n. It jumps from 0 to 50/60/70mph while idle'n. Have you ever heard of such a thing? It also doesnt show me my "real" speed when driving. It just stays at 0 until it feels like jumping. I've tried to reset the ECU by disonnecting the battery several times. The other weird thing is that the Check Engine light kinda dimms and gets brighter now. It didnt do that before. The car runs fine though. Could my ECU be bad?