RPM fluctuate at idle

[Macdamike]

I have an issue with my 2005 LR3 with about 70,000 miles on it.

When the LR3 idles in park (especially in the mornings) and even sometimes at stop lights the engine RPMs constantly fluctuate between 1000RPMS and 500RPMs. If the LR3 is in drive and you happen to step on the gas when it is down in the 500 RPM range it will occasionally stall. Once the car is moving (and the RPMs are above 1000) there aren't any problems.

Has anyone come across this issue? If so, what was the fix? Initially, I thought it was MAF sensor. But, now I dont think so.

 

[CMGRover]

Bad gas? Could be water in the gas. I'd try a gas treatment.

 

[toddjb122]

I had something similar and something was broke in my throttle body.

Might be worth checking, just cleaning could take care of it. Anyway, the problem went away....mostly.

 

[kwlr3]

Mine fluctuates during warm up just as you describe and only during the last minute or two that it takes to get fully warmed up. The colder the morning temperature, the longer and more pronounced the fluctuations. I've brought it up a number of times with the dealer and they have no explanation other than suggesting I replace the accelerator pedal. I have noticed that this occurs during open loop operation (when the engine parameters are being control by a program map) and not during closed loop operation. Every logical explanation that I have offered to my mechanic has been shot down with the reason being that they would all trip a fault code.

Change your morning commute so that soon after you start the engine you enter a freeway at near full power. That will help clear your head and your LR3's.

2005 HSE, 92,800 miles, owned since new.

 

[schafari]

If it is stumbling and sometimes stalling at low speeds such as coasting under 5mph. . . The first thing I would check is the mass air flow sensor, air filter, and throttle body. You can take out the MAF sensor in less than 2 minutes. It is two torx screws. Get some MAF sensor cleaner. Clean it. Put it back in. Ensure the throttle body is visually in working order. Ensure air filter is good. . .

Check the MAF sensor. I did just this on mine on a 3k mile road trip. 20 miles away from any paved road. . . The MAF sensor had a layer of dust from the dirt roads. Once cleaned, the problem went away completely.