2001 Dodge Caravan

Engine Mechanical problem
2001 Dodge Caravan 4 cyl Front Wheel Drive Automatic

i have just changed a broken timing belt on this dodge caravan. I have the timing marks lined up perfectly according to the chilton manual. However, it idles rough and when you press on the gas peddle it starts backfiring through the throttle body. It also seems to have no power when you hit the gas. I did not drive it. I also had to replace the fuel filter. Please help