Here's a fun one to try to diagnose
First off, the car is going into the shop tomorrow to find out what's going on with it. I don't have my odb reader with me so I can't check the codes.
After not seeing many miles for several months, my 05 has been seeing a lot of the highway. This week took me from the NC coast to Central Virginia to Maryland to Northern Virginia to Central Virginia to the NC coast. Driving the final VA to NC leg today something felt a bit off but I wrote it off as the wind. It felt like little minor power dips. Then, on an onramp, I was coasting with the clutch in behind a truck and the engine stalled with the rpm jumping around a bit first. No CEL. Several miles later I just put the clutch in on the highway and let the revs drop down to idle. Spiky rpm and quick to stall. At speed there weren't any problems to speak of. The gear shift was bouncing around a bit more than it should have been and some of the same minor blips in power. After another 40 mins or so the CEL finally lit up.
When I finally was off the highway any time I was at a stop I had to heel toe to keep the revs over 1500 or it would threaten to stall. At 1500 it was running ugly. Obviously not firing on every cylinder. VANOS rattling sporadically. When I finally pulled into the driveway I still had to keep the revs up to prevent a stall. Eventually coaxed it into barely running at idle. Erratic knocking and wheezing from the engine and a burning rubber smell from somewhere Midway in the engine bay on the driver's side.
So... Thoughts/bets on what it is.
Additional probably not relevant information. On the stock navigation screen, nav never loaded in after I stopped to get gas (before the problem appeared). The button to switch between the most recent display would just blank the screen. By the end of the trip the screen would blank on its own but I could wake it up with a button push. The screen going blank only effected the display, not the back light.
