I have a 1988 crew cab dually with a 454 TBI motor. I recently put on new headers, while I was doing that I put in new spark plugs, wires, cap, and rotor. I started it up and was running but it won't idle it has a loping sound to it and then it will stall out. So i replaces the O2 sensor and took it for a drive and it still will not idle it seems to have pwer but something is not right. Any ideas would be great thanks Diesel Dan

 

Check to make sure you got the spark plug wires to the right plugs.

 

Make sure your cap is tight and that the distributor clamp is holding tight. That may be something like an airflow sensor too. Make sure your throttle body is clean too.