natesniper8

I have a 2000 rx300 with 131,xxx miles. This first started on a 18 hr road trip. When we got the the rpm moved up and down slightly but noticeable at stop lights or slow speeds. Someone did fill it with octane 85 when i was sleeping during a fill up or 2. After we let the car sit after we reached destination the problem was gone. I returned back home to MN and there were no problems. I'm not sure it this is connected to the current problem but it could be.

A couple weeks down the road the rpm started to move when I first started the car and continued at slow speed, stop lights. It was real slight and not too noticeable. I noticed it goes away once I hit highway speeds of 60-70mph for a few seconds and then returned to slow speeds/stop lights. Otherwise it continues for all in city trips since i can never reach that higher speed. At one point the check engine light went on and it read p0100 i believe and multiple random misfires. But that light eventually went away a day or 2 later, or my buddy reset it im not sure.

I read another guy on this site had the same issue months back (SRX) and a couple others. I guess motor mounts are likely to cause the problem. But that doesn't make sense to me if it goes away once I hit 60mph. Clogged injectors? I guess one of the motor mounts is hydraulic/oil.. possibly ignition coil? Any help is greatly appreciated, thanks.

Nate

Did anyone ever figure out why the RX300 vibrates at RPMs under 8k? Mine seems to only idle rough when in gear and stopped. If I put it in neutral or park the RPMs go up and it seems to idle fine. The low idle causes a low frequency vibration throughout the entire car. It is extremely annoying. Any ideas?

My 2000 RX develops a similar pattern to the one you describe after driving it only around town at low speeds with little if any sustained highway driving. If I take the vehicle on the highway and drive an hour or two at highway speeds (65-70 mph), the rough idle is gone after returning to town. Repeat as necessary.

HEY SRX! I have had the same exact problem as you this last couple weeks. Mine also goes away when I hit 65-70.. Did you ever end up figuring out what the cause was or were ever able to make that go away??