I have been having trouble with the engine breaking up in my 8 at higher RPMs but only in higher gears. I was not getting any CEL or Codes unless I kept on it and let it persist. Then I got a misfire code.
The dealership diagnosed the problem as one of three intake valve solenoids. (and, yes I know I have ports not valves) But the only solenoids I can find on the inlet manifold specs are the three VDI solenoids (two of these which I have already replaced) and the purge solenoid.
AM I looking in the wrong place?

 

Well if they diagnosed it then they should be able to tell you which one is bad as you actually test each one to determine if they are bad. Either way, a bad solenoid generally doesn't cause a misfire. I suggest finding the factory service manual online and following the troubleshooting guide to try and find the exact issue you are having.

And the Renesis does have intake vavles.

 

Was the misfire the only CEL?
Was it a general misfire code (P0300) or rotor specific (P0301 or P0302)?
Its important to get the whole picture.

You do have intake valves... SSV, VDI, APV, and VFAD (if stock).

VDI is one of the three solenoids in that group behind the intake manifold, not three VDI solenoids.
From top to bottom its AIR, SSV, and VDI solenoid.

Probably. Best place to start looking is right here on this site.
Once you find out which CEL(s) you're having, use the search on this site to find out what others have encountered and how to go about repairing.
You'll find that misfires usually end up being a few common possibilities.
Also through searching you can find ways to troubleshoot the solenoids yourself if you want to tackle that.
I could list all sorts of common components to replace if you have the $$$ to throw random parts at it, but hopefully through troubleshooting knowledge and understanding, you'll be able to narrow it down some.

The service manual is a great thing to have and as redcivic mentioned, use that to help in your troubleshooting.
Search this site and you'll likely find a link to the service manuals.

And for future reference you should also list your vehicle's mileage and year, any aftermarket components that you know of, if its had a compression test (and if so, what were the results), and any recent work that may have been performed (even if it doesn't seem applicable).
Hope this helps get you started down the correct path. Good luck!

 

Thank you guys.

 

Not trying to steal your thread of anything but I have the same problem. My engine struggles at high rpms. I'm throwing a p0076 - intake valve control solenoid circuit low bank1, p2259 secondary air injection system control circuit low along with p0455 evap emisison control system leak detec..(gross leak, check fuel cap, etc.) I know we have three solenoids which they are ssv, vdi and air solenoid valve, but when I went on google, there is also a ssv - secondary shutter valve and ssv- solenoid switch valve. If I need to chance a solenoid then I should change all three of them but I don't know which one I need? are these the right ones? How do the vdi, ssv, air solenoid valves look like?