Help, x5 running strange
 

Ok, so first off I have an 01 X5 with the 3.0 and Auto. 107K miles.

Last week I accidently put in regular unleaded (was tired and not thinking), only about 1/4 of a tank when I realized it and stopped.

2 days after that I was in line at a drive thru, when all of a sudden my X5 started shaking. When I would accelerate, it was bogged down and it had no horsepower. RPMs were reving high until it hit about 4th gear it then felt smoother. At every stop light it was shaking though.

I went straight to the gas station, put 93 octane fuel, and it went away. I didn't siphon out the old gas. It did again yesterday, so today I put in an octane booster with more 93 octane fuel, and it still does it. It will only start to do it when its stopped, and usually goes away after driving a bit, but then will come back after a while of being stopped (like at a traffic light). When it happens, it accelerates like if there is no air going in or a clogged injector...not sure...just bogged down is the only way to describe it. The shaking is only when I'm stopped.

What could be the problem??? It was running great prior to that, but now I don't know what to do? Any ideas what it could be????

:dunno: :wow:

Well, it is very unlikely that it has anything to do with your quarter tank of regular fuel.

Get the codes read, at a dealer or independent shop. That is what the self-diagnostics are for. They will at least point you in the right direction.

give it an little tune-up, ( new spark plugs, air filter, fuel filter)
and get a code reader, check for misfire

100K is tuneup time (new spark plugs,etc) - has this been done? - maybe that quarter tank had water in it? - high ethanol gas sometimes results in what you describe - tried that stuff once and it took 3 tankfuls to clean it out and get back to better mileage and performance

looks like a misfire is exactly what I've got. I got the following codes from a basic OBDII reader.

P0300
P1353
P1351
P1083
P0171
P0300P

2 of those are lean fuel, the others have to do with misfires. Any ideas what this could be? Could it be simple, or is it for sure a really bad situation?

:wow:

P0300 and P0300P Random Multiple Misfires
P1353 Misfire Cylinder 6 With Fuel Cut-off
P1351 Misfire Cylinder 5 With Fuel Cut-off
P1083 Fuel Control Mixture Lean (Bank 1 Sensor 1)
P0171 System Too Lean Bank 1

you might also have a vacuum leak. Vacuum leaks can give all these codes. Check vacuum hoses in engine.

I had a the same problem a while back on my 01. I found it was the air ilde control unit. It's a little black box located in the drivers side on the engine. About 2.5 inches by 6 inches long. It has a sensor hooked up to it. It is very easy to replace..about 10 minutes. The part is a bmw only part and if I remember correctly its about 135. If you pull the part out and look at it there is a round flapper valve looking thing with a arm to make it move. Just by looking at it you will know if it is broken or not. Hope that helps. I was getting the same codes you were.

I have an '05 X5 with 130,000 miles (yes, I am the original owner). I would advise changing your fuel filter and looking at the plugs. In the future you may want to look at a regular schedule of TECHRON every 3,000 miles with your regular maintence.

As while the idle control valve can act like a vacuum leak, the part you just described is the "DISA flap" and controls the variable intake runner legnth system. The idle control motor is the same one used in other BMW models, the lil silver can just above the throttle body.

culthero, also check the smaller branch of the intake boot to the throttle body/idle control, it has a habit of cracking in the turn giving unmetered air to the system. And check the "cyclone valve" crankcase vent valve. It is under the intake. With the engine running rough at idle, use a can of throttle body cleaner with the red tube and spray down areas you suspect for vacuum leaks, the engine will smooth out and idle higher when the leak is sprayed.