I recently noticed that my truck performance was considerably worse than usual. My truck is 2015 5.3L and has right at 30k miles. I bought the truck new and from the beginning averaged about 16-18 mpg around town. I would get 20-23 mpg on the highway. The last month I've noticed I'm getting about 12-14 mpg around town and only slightly better on the highway.
Interestingly enough, I got a call from my dealer that OnStar/GMC has notified them of "poor performance" on my truck and I need to bring it in.
Well, like many others I'm sure I avoid the dealership at all costs. The whole process is an inconvenience and their prices for everything are ridiculous.
I'm going to check air filter, oil level and tire pressure. I don't have any lights on or notifications from the truck itself, everything appears to be fine.
I'll report back when I find something out, but taking to the dealer as a last resort.
Josh B.
