Accelerator Pedal feels heavy to press at times
I had just about all maintenance done to my Max this past summer. Tune-up was done, I did a fuel induction service as well, yet when I accelerate (during normal driving, of course), the gas pedal feels heavy at times and I try to press the pedal a little further w/o choking the engine, the rpm's stay where they're at for a little while, as if its hesitating at 2K rpms. After this occurs and when I take my foot off the gas and shortly after I press the accelerator, the pedal feels normal again. SES light came on for a while earlier this week for a KS and a P0153 (O2 Sensor Code) according to Autozone's diagnostic tool, then turned itself off. What can be the cause for the occasional heavy pedal syndrome. I have over 116,700 miles.