My 99 4.6 4x4 has developed a miss. It is most noticeable when it is lugging before a downshift. I can also feel it in passing gear on the highway or accelerating onto the highway. I have already cleaned my MAF but don't really know what to do next. The service light is on and it is throwing p1000, p171 and p174, lean on banks 1&2. Coil packs? O2 sensors? I checked for vacuum leaks along the pcv hose but didn't find any.Any ideas?

 

Look closer for a vacuum leak. The PCV elbow is behind the intake manifold by the firewall and is impossible to see, you have to go for it by feel.

How old are the plugs and wires, and what brand are they?

 

The plugs are about a year old and are Bosch. Is the break in the pcv hose usually under the insulation in the line? I checked the ends of the hose and didn't feel any breaks in it. How do I get the pcv line out of the manifold/ back of the tb to do a closer inspection? Thanks

 

The wires are 1999 Motorcraft originals, have never been replaced.

 

Get rid of those Bosch plugs. They don't work worth a crap in Tritons. Put stock Motorcrafts back in, and if you need wires use stock Motorcrafts.

For access to the PCV elbow, you can pull the throttle body. Might not be a bad idea to do that anyway, so you can clean it.

 

Just verified that the elbow is not the problem by pulling pcv out while running, it had a surging rough idle, like it wanted to die, but would rev to prevent stalling. With the pcv in place, it has a smooth idle, like nothing is wrong. I will put motorcraft plugs in tomorrow and see if that fixes it?

 

To follow up, I put in Motorcraft plugs today. The codes have not come back and the stutter is gone! Thanks for the tip to dump the Bosch plugs.