Q: Performance Restricted Warning and Check Engine Light - 2004 Jaguar XK8

asked by on

I have a well-maintained car with 167,000 miles on it. It's been running great. A while ago, while I was on a trip, I had to fill in the gas tank with a middle grade gas instead of Premium I've been using. The next day, the warning came on indicating the restricted performance. After a while during driving, the warning disappeared. I filled in Premium after that several times. I took the car to a shop where they analyzed it and had the computer reset. However, the check engine light came on illuminated in yellow. It was followed by the same restricted performance warning. These disappeared when I filled the car with premium again. Why did this happen? Is there anything I should worry about?

Hello. The engine knock sensor is retarding the ignition timing to match what the lower octane fuel can support in terms of “timing advance.” There is nothing to worry about. The engine computer is just operating the engine so as to minimize detonation or pre-ignition (aka “spark knock”). Given your description though, you should always use premium fuel. If the light continues to come on or you begin to notice drivability concerns, I recommend having a professional mechanic, like one from YourMechanic, diagnose the Check Engine Lights and warning lights in order to have this corrected.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Performance Restricted Warning and Check Engine Light - 2004 Jaguar XK8

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Why am I getting warning messages in my 2006 Jaguar XK8

Hello. If you had gotten this warning message along with an overheating condition then I would be a little mindful about a possible cooling system issue. These can come and go sporadically if the issue is something like a thermostat....

Q: my transmission is "slipping" 3% of the time

Hello. From what you describe, it would appear that your transmission is beginning to slip. This can be caused by many things. The first thing I would do is check the vehicle's transmission. Automatic transmission use fluid pressure to operate,...

Q: Will my 2010 Ford F150 benefit from a performance exhaust?

Warped manifolds are a well known problem on the 5.4L engine. My personal F150 has a noticeable exhaust leak from the manifolds on cold start, but goes away once the engine warms up and the manifolds expand. As for adding...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...