I swaped what I thought was a 99 civic ex motor inot my 97 civic ex, but it tured out to be a dx motor. The honda salvage yard said it was a 99 civic ex motor with 48k miles. So we just used the wireing harness from the old motor. When I got the car back it ran great for a while then it started to loose power. It was like a dead spot in the lower rpms at first then started to happen more often. And the motor was drinking coolant. So I had the headgasket replaced. now its doing the same thing. It looses power then the power comes back (feels like no gas for a while) and it diong this much more often. Sometimes I think the car is going to cut off. What do you think is wrong? Also I got smoke coming out the tail!