You're probably a tooth off with your cam timing, which is easy to do since the crank sprocket timing mark is so wierd. I found you can be a tooth off and it will still seem to idle and accelerate just fine - but you will get a check engine light and error code. The best way to avoid this situation is to paint your own crank mark before removing the old belt, but I guess that's water under the bridge at this point. Do you know what code number is accompanying the check engine light?