My check engine light is on at the moment. Has been for a while. If I remember correctly it said it could be a possible vacuum leak. I replaced the very top hose that they redesigned and made ribbed several years ago. I can't notice a vacuum leak anywhere. When I am driving above 70mph my light comes on and says cruise not available. Hard to search for on the forum since it will only search the term cruise. This message soon goes away once I reach lower speeds. Any thoughts?

 

Stiffler, sounds like a bad spot on your Throttle Position Sensor (TPS). Essentially the car doesn't know where the throttle is located. Since the car is throttle by wire, not knowing where the throttle is makes it hard for the computer to do the controlling as it can't get any feedback. Atleast when your foot is on the gas, you are acting as the feedback for the computer and therefore it will control the throttle by putting a certain amount of voltage on the actuation motor and if you are going too fast, it figures you will let off of the gas.

You can verify this by connecting up a multimeter across the 2 pins of the TPS (inboard side of the throttlebody) and as you manually move the butterfly valve inside, you should have a nice increase in resistance (goes from like 50 to 250 ohms as I recall, but don't quote me on that). All you are looking for is a nice smooth change. If you see it jumping around, you have dirty/dead spots in the TPS and you need a new TPS.

The other thing to look at is the wiring going into the throttlebody. It is possible that you have a little bit of insulation damage and when the motor is under load, it is putting just a little bit of strain on the wiring, leading to your issues.