I just purchased a 2011 XKR with 8,500 miles. I've been driving it in town and it runs superbly; however, 2 weeks ago I took it out on a longer road trip and experienced the engine misfiring. I'd been driving on highway at around 80 mph (this is Texas) for a couple of hours and entered a small town requiring me to drop to 35mps and stop at traffic lights. As I accelerated from a complete stop the engine would misfire and the car would shudder. Needless to say, this was quite annoying and disturbing. Once I got back on the highway the car ran fine. I did run a bottle of fuel injector cleaner through the system once I got home. Subsequent trips back home didn't produce any repeat occurrence of the misfiring. This past weekend I took the car out of town and once again had it do the exact same thing, accelerating from a complete stop after hours of highway speeds and yet another round of misfiring and shudder. I wasn't gunning the engine just a slow steady acceleration from a complete stop. The engine light did light up for a period but then went out. Back on the highway the car ran fine. I do have a warranty and am taking the car in to have the codes read. Has anyone else experienced anything like this on their 5.0 SC engines? Any feedback would be appreciated.

 

With such low miles my guess is an anomaly, likely bad gas (in the car not the driver). The chances of it being a bad coil or injector are very very low. Plug in a OBDII reader let us know if any codes show up, put in a new fresh tank of gas and you should be fine

 

Texas is a big place JF, can you narrow it down a little?