2007 Compass - High whiny engine at startup and low speeds.
Hello all. I have a 2007 Compass - automatic transmission with almost 57K on it. I have been the only owner/driver. Past relevant problems include a blown fuse that was causing the headlight and interior lights to malfunction (fixed) and a battery that leaked all sort of acidy goodness on the positive terminal. New battery and I'm getting more corrosion about 2 years into it.
Problem lately has been a high idle when I first start the car, up to about 1750 RPM. Within 30 seconds the idle drops to about 500-750 which in itself hasn't been alarming, but started the same time as the following issue The other issue is that the car has had sort of a high whine when I'm traveling less than 20 MPH (like around my neighborhood) and seems to have a little delay and even a small hiccup in downshifting. If I shift the vehicle into neutral the whine goes away and doesn't come back if I shift back into drive. The car seems to be driving fine - certainly is ok at high and constant speeds, but the whine is noticeable at lower speeds and city driving with a lot of starts and stops and turns. I don't like the high whine and wonder if it portends problems in the future.
I live in Utah. It has been between 90 and 105 F for several weeks.. The car is in the sun all day. No noticeable change in gas mileage which has always been terrible (18-22 MPG the entire life of car)
I am wondering if the problem is transmission related and whether I should have the 60K service sooner (because that includes a transmission flush) or if it is perhaps battery related. Engine oil is fine, but I am also due for a checkup.
TLDR? High whiny engine at startup and low speeds.