2001 E53 - Loss of Engine power issue

[MiCkEy]

I am hoping someone can help me with this strange problem.

Sometimes from a cold start, the truck feels like it is hauling a 8000 pound trailer in the back and the "mpg gauge" is pegged all the way to the right. There is no hesitation but it does seem like something is holding the vehicle back and it seems as if the truck stays on the 3rd gear for along time with little power. This happens randomly and if I restart the truck, it's as if nothing ever happened and it drives like new. The occurrence is very random and most of the time it runs fine.

Other thing I did notice is when that happens, on a red light, the idle RPM is just under 1000 mark. When the truck runs normally its always around the 550-600 mark. Maybe this is related.

In the past I have changed the ICV, camshaft sensor, belts, water pump, fan clutch and have cleaned the MAF. Can this be the DISA valve or the MAF? There are no codes and I don't see or hear any vacuum leak or a whistling sound.

[MiCkEy]

No one? I guess I am the only one who have had this issue....

[amacman]

I have the same issue sometimes on a 740 i . been recommended to disconnect the MAF plug to see if it makes any difference which I have not done as it was ok all summer and only recently had the symptoms again .
It is having maintenance at the moment so can`t try unplugging the MAF .

[MiCkEy]

I tried that and the vehicle went into "trans failsafe mode"

[btmed]

I also tried the unplugging of maf and got trans failsafe mode. Mine 2001 x5 3.0 121k. Sort of the same problem that i just resolved. A little opposite than yours. Would start up and run great but when it finally heated up, about 10 or 15 miles into drive, it would suddenly feel like it was running on five cylinders. I could pull over turn off start back up and it would run fine until i put a load on it, punch it or begin an uphill climb. Then it would revert to running like crap but could pull over turn off restart and fine again.Stealer did find one bad coil and told me intake exhaust cam sensors were faulty. They were aftermarket bwd. Took them out and returned to oreillys where they gave me 2 new ones. Still same prob. Took them back and they refunded my money and went directly to bmw oem brand. Installed and problem resolved.

Next up changing out leaky oil filter housing gasket.

[MiCkEy]

Hmmmm..I do plan to clean the oxygen sensors this weekend and looking at a new fuel filter since I am close to the 100K mileage.

[btmed]

Just reposted peake 89 code. After one day the problem is back. Code 89 plus 01 - ignition coil cyl 2 & EF Misfire cylinder 2. I just swaped coil in cylinder 2 with cylinder 4. Now i am getting code 02 - ingintion coil cyl 4 & F1 Misfire cylinder 4. Must be the coil & this is the coil moritz bmw changed out two weeks ago oem. Still researching 89, jet stream pump.

[wallyx5]

Check the intake boot and make sure it is not torn or cracked. I had a similar problem as you described and it was due to the elbow boot being torn.

[MiCkEy]

Thanks Wally. Installed the intake boot 10k miles back and looks well and not torn.

I also took intake O2 sensors out today and I think they are still the originals. I am close to 100K and I may swap them with new ones anyways.

Originally Posted by wallyx5

Check the intake boot and make sure it is not torn or cracked. I had a similar problem as you described and it was due to the elbow boot being torn.