I drive the SuperV8 almost daily. I consider myself very "in tune" with my cars, being able to detect irregularities in noises, handling, vibrations, etc.

About a week ago, after a 2,000+ mile road trip, I noticed that when drawing to the end of a stop, there was a slight vibration/rough idle similar to an engine getting ready to stall also comparable to how the car runs when the A/C is switched on, like it's running a little rough. I drove the car for the first half of today with no issues but this afternoon ran into a problem.

About a minute into my drive, I observed a series of error messages: parking brake failure, DSC failure, engine malfunction, etc. The engine then began running really rough and would no longer accelerate. I came to a stop, turned it off and restarted. No issues, car ran fine for about a mile or so, then it happened all over again. Turned it off again, and tried to drive it. After the third attempt the ENGINE light came on permanently and I had to continue this routine all the way home.

Wondered if anyone has any suggestions before I venture to the dealer tomorrow?

About 3,000 miles ago I had the oil, coolant, fuel filter and air filter replaced.

 

These are a classic symptom of throttle body failure, which is a common problem. The throttle body probably needs to be replaced or rebuilt. Search the forum for details and rebuilders.

 

Does anyone have instruction on how to replace the throttle body? Is it something that can easily be DIYed with hand tools?

 

The battery is about 6 years old, could that have anything to do with it?

I did read through every post I could find regarding the throttle body and it does sound similar.

 

Okay just replaced the battery with an Interstate MTP93, the best they have. Engine is running a lot smoother now, no change with the A/C running. No more errors either. Hope that is it. Planning on checking the codes later today.

edit: oh and the check engine light went away

 

Ran diagonistics:

P2135 TPS/Pedal position/Electrical fault

P1111

 

Took the car to the dealer today. While they believe that it could be either the TPS or pedal position sensor, they said that it appears the issue was likely related to the old battery as power issues can trigger those codes.

If the problem comes back though, they will replace both.

 

Congratulations. Not only did you fix the problem, you have a fresh battery out of the deal. Hopefully, the codes will stay cleared.

 

AND you celebrated by replacing your wiper blades!

 

Indeed!

 

Just thought I'd add a comment for anyone researching these types of problems. Even though my comment deals with an X308, it is eerily similar ...

Back when my 2000 XJ8 was about 7 years old, I started having lots of strange codes setting the CEL - my independent shop here in Dallas that I really love and trust told me that the battery needed to be replaced. Despite how much I trust them, this just didn't sit well with me, since my voltage tests and load test on the battery all said it was fine, despite the fact it was 7 years old.

But I relented and let them change the battery anyway, telling them that if ANY of the problems persisted, I would expect a refund on the battery. Guess what - a complete fix - that car ran perfectly without any codes or other warning light issues for another three or four years until it got totaled!

Despite the fact that the X308 and X350 are very different cars, all the evidence does seem to indicate that they are very sensitive to old batteries that may be having occasional voltage or amperage issues.

 

This begs the question: how many repairs have been made when perhaps all that was needed was a new battery?

It is interesting because I have had several cars from Lexus, Mercedes, etc that I kept long enough from new that they needed new batteries and every other time it was because one day the car just would not start, never before have I encountered malfunctions like this due to a bad battery.