Hi, I purchased this car from a friend at a very low price about 2 years ago and I noticed from the first day I had it, that it idled high whenever I would stop. It seems to be much worse when it's cold or when I have my A/C on. Recently I had my CTS (coolant temperature sensor) replaced and that seemed to fix the idling issue for about 2 weeks, then it went right back to how it was just a few weeks prior.
Also, within the past few weeks I have noticed some hesitancy in acceleration when it shifts at around 35-40 mph. If I get on the highway I can almost floor it, but it doesn't accelerate much at all and it really lacks power accelerating after a stop. The service engine soon light will blink a few times and then shut back off. Because of these two problems, I really hate driving my car even though it's never broken down on me.
I have looked online and seen multiple solutions to both problems, but have never seen someone who said they actually worked. I have spoken to multiple auto mechanics about this and haven't gotten any advice. Please help!
Thanks, James