Had the car for about 2 years. The main problem is the occasional Restricted Performance Mode. After you run it for about an hour it will go away. I have also figured out that if you run it once a week or so it never comes on. Do these symptoms indicate which sensor is bad?

 

Might even be a failing battery.

You'd have to try an OBD tool in the hope of at least a pending code or bogus live data value(s).

 

Do you keep a battery maintainer plugged in when not using the car?

 

Battery is only 3 years old.

 

There is a drain of the battery even when the car is locked, so the voltage may be low when you start it. You need to check the voltage before starting, and the gauge on the dash is not accurate. You should have at least 12.4v, better 12.5+.

 

Could be un-metered air getting in thru a cracked accordion tube - intake. But, you really should get an OBDII tool/reader. They are not very expensive nowadays, and every modern car uses on board diagnostics (OBD). A low battery can cause a bunch of issues also (run it once a week or so ?)

 

When ever I'd get the restricted performance mode warning, I always lost my cruise control at the same time. I figured they must be related, so I snugged up all of the electrical connections at or near the throttle body. That was 2 years ago and I haven't had the warning since.