I have an '08 SL hatch with the CVT. Normal idle range for the tach is 600-700 RPMs, but when I'm idling in drive for a few minutes the RPMs will drop to around 400 and the engine will stumble like it's about to die. Immediately afterwards the RPMs jump to around 800-900 for a few seconds and then the needle settles back to the normal range until it happens again. I've had it happen more than once when sitting for an exceptionally long time at a drive thru.
I noticed this problem last fall, but it went away over the winter and just recently returned. It only happens when the car is in drive. If I idle it in park, everything is normal. The AC isn't on, so I don't think it's the compressor. My car's AC compressor sounds like leaf blower at idle, so I'd hear it for sure. It even happens when the blower fan is off. I doubt it's dirty injectors, because I've owned the car since it was new and use Chevron gas. It's maybe had 40 gallons of fuel from other companies total. I also run a bottle of Techron through it every 5K or so.
None of the idiot lights are on, and I just cleaned the MAF sensor and changed the air filter a couple of weeks ago. The engine starts right up on the first crank.
Any idea where the problem might lie? The engine hasn't died on me yet, but I'd hate for it to progress into a serious problem.
I noticed this problem last fall, but it went away over the winter and just recently returned. It only happens when the car is in drive. If I idle it in park, everything is normal. The AC isn't on, so I don't think it's the compressor. My car's AC compressor sounds like leaf blower at idle, so I'd hear it for sure. It even happens when the blower fan is off. I doubt it's dirty injectors, because I've owned the car since it was new and use Chevron gas. It's maybe had 40 gallons of fuel from other companies total. I also run a bottle of Techron through it every 5K or so.
None of the idiot lights are on, and I just cleaned the MAF sensor and changed the air filter a couple of weeks ago. The engine starts right up on the first crank.
Any idea where the problem might lie? The engine hasn't died on me yet, but I'd hate for it to progress into a serious problem.