Over the last 8 months I've noticed that this vechicle has problems at idle, the engine once has shut down because it was idle'ing too low and wouldn't start for a about an hour or so? At stop lights I can see the RPMs vary between 500 - 1500? The car has about 106,000 miles, I'd like to keep it going for several more years, as I hear these cars can last for a while if properly maintained. Any insight would be great. Thank you.