My exauhst hasn't cleaned itself in at least four or five thousand miles. I got the truck with around 22k on it. When I first got it it was saying cleaning blah, blah as I was coming up my driveway but would never cylce. I assumed it was because of the gravel and dust that just set the censor off. After that it did a cleaning cycle once or twice. But I pulled a car around a thousand miles to Myrtle Beach and back and another thousand miles or so to Jacksonville, FL without it cycling. It still hasn't cycled since then. Truck seems to run fine, mileage might be a tick less. It did feel like it had a little less power towing but nothing major. Should I be worried?? I plan on a delete pipe soon anyways.