Did a tune up over spring break. It doesn't feal like I'm not getting spark. There isn't a loss of power at low RPM's all the time like it would be if it was a bad spark plug. Only for half a second every two or three minutes. The rest of the time it runs perfectly normal. Its not like miss firing. Its worse when it happens but not constant. There is also no check engine light. Well no check engine light for this problem. The wiring for the knock sensor is messed up so after I run the car for 20 or 30 minutes the check engine light comes on. Also its not getting worse which suggests to me its not the O2 sensor or a bad spark plug because that would be a constant problem and it gets worse over time. can someone tell me if my logic is correct?