All I can figure is that a vacuum line is letting air in, throwing off the ECM. Since the TPS and MAF are working properly, the extra air must be confusing it. Sound about right?

Either way, I need to get some new lines on this ride.

 

Any DTC's? Which engine?

 

Yes, P1151 and P0401(whichever one is the EGR code). Guessing P1151's either a bad vacuum line, or possibly bad O2 sensor... it does have 190,000 miles. The EGR code - gonna pull the EGR tube and clean it out ASAP.

It's the 5.4 engine.

 

FIXED! I plugged the business end of the pcv valve, and she drove smooth as butter. Not even $5 on a new pcv valve, and the herky-jerky is a thing of the past.