Hi all! Sorry this is so long, but I wanted to give as much info as I could. I own a 2015 Mirage ES with 140,000 miles on it. I purchased it new, and probably close to 90% of the miles are easy driven highway. A few months back, I noticed what I thought was a slight slipping of the cvt. About 15 miles into my 40 mile commute, with steady pressure on the accelerator, it would suddenly drop approx 500 rpm, but would "surge" right back to where it was previously. If I kept steady pressure on the pedal, it would do this several times, back to back to back. If I increased or decreased pressure on the pedal, it would stop and not happen again on that commute. This would happen periodically at first, then daily, then regularly to AND from work, also getting more noticeable. No cel and no blinking gear indicator. I took it to the dealership where they found no codes or anything wrong, nor could they reproduce the symptoms. They did update the ECU, as it was a recall, and it maybe seemed a little better right after, however, it has progressively gotten worse again.
NOW.... Almost home the other day, it started doing it, which was strange (usually only happens approx 15 miles into trip). I exited off the freeway, came to the stop sign, and when I pressed on the gas..... no response. Car didn't stall, but no increase in rpm's, no movement, nothing. I was on a slight decline, so I did slowly roll forward and with pedal still pushed, it finally sputtered a bit, then SLOWLY increased in speed. Thankfully I made it home without needing to stop again. I stopped at the beginning of my driveway, and when I stepped on the accelerator, nothing. I tried "B" & "R", nothing. I shut the car off, started it back up, put it in "D" and it drove normally into the garage. I unhooked the negative battery cable, stepped on the brake for over a minute, then left cable off for several hours. When I started it up, I let idle for 15 minutes before taking on a short test drive, and it drove normal. I took it on a couple more in town drives, and they were normal, which gave me hope. Then I drove it approx 10 miles on a non busy hwy, came to a stop, pushed on accelerator and nothing. I was able to get it home again after turning it off and restarting it.
Currently: Still no cel or flashing gear indicator. I've added a bottle of Techron to the gas tank, drove it on back streets a bit and let it idle for a while.
I did do a cvt fluid drain & fill with external filter change not long ago. Can't remember if early symptoms had shown up before I did this.....old fluid wasn't horrible. However, I'm thinking more along the lines of maybe accelerator pedal/sensor or maybe fuel related?
Additional notes: When accelerator pedal isn't responding in "R, D, B", if I put in "N or P", rpm's do go up with pedal pressure, although with a very slight delay to the response. MPG's have seemed to drop a bit over the last year or so.
Thanks for taking the time to read my ramblings and for any input! God bless!