My 745li is idling up and down at 1500 rpm

It dont idle like this when sitting in park but only as you going down the road and its at 1500rpm where it goes up and down. If anyone ever experienced this please help me out on the fix and please be detail thanks.

Originally Posted by los2much

It dont idle like this when sitting in park but only as you going down the road and its at 1500rpm where it goes up and down. If anyone ever experienced this please help me out on the fix and please be detail thanks.

It's your tranny acting up.

I think it maybe flywheel getting stock.

it has no problem changing gears

I know I have the same problem. it happens only when it time for trans to downshift,but if u use manual mode it work just fine. Take a look at flex disk maybe it broken

My car does exactly the same thing. Its pretty annouying. Same as you tranny shifts smooth as silk. But if im coasting down the road foot off the gas the rpms will go up and down slightly. Can't figure it out.

I wish some experience techs would chime in.

Try the infamous PCV valves or also known as crank case ventilators. I have attached a link so you can see what they look like

http://www.ebay.com/itm/OEM-BMW-E53-...-/160688315458

It is good thing to change them but it has nothing to with the problem

Hello, I have same problem even changed MAF Sensor....really annouying, hope can have some suggestion & solution here.

I have same issue, only when car is cold.. for first few minutes of driving, if it drops down to 1200rpm or so it will move up and down, after it warms up its gone.. I first thought tranny, but I am wondering it it has to do with motor.. I think maybe motor is not running at 100% and is making the tranny shift "off" maybe a little power short? who knows, really discouraged with these cars after reading nothing but problems with everything..

Originally Posted by SFbay

It's your tranny acting up.

Well I have been having this issue every morning when I take the car out of the garage.. It happens for the first mile or so then goes away.. I couldn't tell if it was the tranny acting up or the motor running weird.. well today I threw it in M mode while going down the road in 5th having the issue and it remained, it's not the tranny shifting/searching, it's something with the motor. Now I don't drive hard, but I have no idea how the PO drove.. anyway, I noticed when I fired it up the other night when it was cold I could hear the exhuast while I was leaning in the trunk and it sounded a tad bit rough and I think I could smell a little fuel.. anyway, since then I have replaced the stock plugs which were shot with new Iridiums. The coils look to have been done around 07 because they all had an 07 date (MM/DD/YY) of the same 07 date.. I took the MAF out the other night which looked brand new, but I cleaned it anyway.. any other ideas?? Thanks guys!!

Guys if this is not happening when idling in neutral or when stopped in drive and is only happening when the car is coasting then its your torque converter. Check fluid level in the tranny...if it is properly filled then if you want to fix this issue then the torque converter has to changed.

Basically when the engine is not under load and the car is allowed to coast the wheels are freely spinning and the driveshaft is moving faster than the engine flywheel. The torque converter is responsible for doing torque manipulation to counteract that speed difference and keep the engine RPM constant. When the torque converter is not working right it will not do its job properly and therefore you will have the idle fluctuate.

This is not happening when at idle or coast.. When the car is cold for the first mile or so if you give it throttle everything is fine, but if you are feathering to stay at speed limit the tranny will drop into such a high gear the car will run at 1200RPM, and that is when I am getting the fluctuation.. while giving it throttle, if I let off gas then it goes away..