RPMs drop when stopping

[nigeyboy]

Mine started doing it after I had it serviced at the stealer. They also replaced some hoses - they can't cure it & I'm livid !

Any help would be really appreciated.

M

[Ahmed303]

Vacuum leaks are a Bit*h to trace. You may want to have another tech to give you a second analysis. Any codes or lights?

[nigeyboy]

Thanks Ahmed

I had the SES code originally but the car ran fine. The dealer cjanged the vacuum houses - the light went off but it now runs bad. They won't have it - have changed the gearbox oil because they thought it was transmission related!

I've had it since new, (7 years) & know when it's not right.

Can I check the hoses myself - which ones are they ?

Appreciated.

[Ahmed303]

There are several including the Jet pump (#1 of the first diagram). If you post the last 7 digits of the vin # i can try to look up symptoms on the TIS later tonight

RealOEM.com BMW E53 X5 4.4i Vacuum control - engine

RealOEM.com BMW E53 X5 4.4i AIR PUMP F VACUUM CONTROL

[Hit Redline]

Originally Posted by Marceltj4.6is

Yes 4.6is. Premium gas only. I just put an air intake on it and that's when I started to first noticed it. I'll prob try putting the stop box back in and see if it continues.

What intake did you put on?

I installed the Dinan CAI some time ago and I recall the instructions have you cap off one of the vacuum lines and install a little breather on a hose that ran into the factory air box. The breather is specific to the 4.6.

[Ahmed303]

nigeyboy...Here are a couple of things popped up when put your symptoms in the TIS. It may not be vacuum related but Fuel Pressure related.

[sunny5280]

Originally Posted by Marceltj4.6is

Hey everyone,
Has anyone ever experienced the RPMs dropping very very low when coming to a stop? They kick back up but then the car jerks a little. Almost like the engine is about to stall.

I had a similar sounding experience with my 2000 4.4i. Turned out to be the control valve assembly in the transmission. Replaced it and the problem went away.

[nigeyboy]

Thanks guys - I'll investigate this & report back.

Appreciated

[digitaljok]

Originally Posted by meltdown325

I have the same thing, but it only seems to happen when decelerating slowly, almost coasting up to a stoplight. It feels like the trans is holding onto the gear a little too long before releasing, thus lugging the engine a hair below the normal idle RPM. Mine won't do it if I have it in Sport mode. No other problems, so I assume its just some manifestation of a glitch in the trans shifting software.

At first I worried about it, but now I just don't care about it. It does it every now and then, it has done it since I got the X, and 10,000 miles later it is still the same.

This is my exact experience with a 85k mi 2003 4.4 as well, but it has only started happening at maybe 80k. I agree that it feels like the transmission is not downshifting in time and thus drops below the idle RPM. But the problem is not consistently reproducible, so it will be hard to get diagnosed. I'm thinking of changing the fuel filter at around 100k (for the first time), wonder if that will have an effect if it's possibly fuel pressure related? Otherwise it may be even harder to pinpoint if it's a vacuum related problem. Any other updates on this issue?

[meltdown325]

My X5 (2001 4.4) now has about 104k miles, and is still going strong as an ox. As I stated in April, my X has been doing the weird RPM drop occasionally since I bought the X with 85K miles.

I haven't noticed the problem getting any worse over the past 20k miles. I am almost certain that, at least in my case, it is not a vaccuum or fuel delivery problem. It does it so randomly, and never does it in Sport mode, which still leads me to believe that it is a tranny software/control issue.

I've moved on from worrying about this issue.