We have a 99 f-150 with the 4.6 engine. We had a code p0304 and p0153. I cleared the codes and replaced the plug and wire. Now i still get code p0304 but the p0153 hasnt came back. Instead p0133 came back along with the cyl 4 misfire. Could the 02 sensors be the cuase of the misifre?

 

Your due for replaceing them all. That probably the problem.

 

The O2 sensor won't cause misfires.

Look for problems in the ingition and fueling systems first, then base engine mechanical concerns.

Swap your coil packs and see if the misfire moves to the other side. If so, you need a new coil pack.

Steve

 

So if the front 02 sensors cant casue a misfire and i have replaced the spark plug and plug wire where do i look next?

This engine doesn't have coil packs.

 

Say what?

I does not have COP's (coil-on-plug), but it certainly has 2 coil packs.

Hint - just follow the plug wires

 

Yup , you have 2 coil packs