My S5 starts popping at around 6k rpm and it won't go any higher. I thought at first it was the TPS, but I got that adjusted correctly. Then I thought maybe it was the exhaust leak, but I just got that fixed and it is still having a problem.

In the mean time I have learned that my car has no emissions equipment. From the reading that I have done, the lack of air pump and solenoids are causing the 6 port actuator to not open.

Is the 6 port not opening causing the engine to suffocate and not rev past 6k rpm?

 

Well after two weeks of looking, I found that the trailing wires were switched. So all is now well.

 

Embarrassed, but happy all at the same time!

 

Exactly. It was right in front of me the whole time. I just didn't think to look at the coil packs. The PO replaced the plugs and wires before he sold it, and didn't really drive it much after.