Part throttle hesitation-3.0L X3
 

Hey all,

I have a 3.0L 2005 X3 6MT with about 70K on the odo. I have noticed over the past two weeks some part throttle stuttering/bucking (minor) while acclerating and generally around the 2800-3500RPMs (intermittantly through to red line) is when it begins. Honestly it feels like timing being pulled, or a little bit of fuel starvation. It doesn't only happen on part throttle either, it happens on WOT as well.

I have had all my inspections to date and am about 5000 miles from another oil change/inspection. I was wondering if there were any other experiences and maybe the cause was fuel pump/filter, bad plugs, etc. Also i don't have any indicators lights telling me something is awry?

This has occurred on 3 separate tanks of gas, and i have not put any "fuel injector cleaner" since i don't believe it truly works. So i don't think it is 'bad gas" and i always put in 93/94, yet from different stations/vendors.

Any thoughts? I am handy enough with my Evo so i can address minor repairs, so i thought i would poll the group to see if anyone had anything like this in their history?

Thanks a lot,

Jon

No thoughts so far huh?

Does it feel like maybe the vanos (cam timing advance) isn't kicking in? The activation solenoids may be sticking and/or maybe the vanos units themselves sticking internally sometimes.

Just one of many possible scenarios.

fuel system cleaners do truly work
may not solve the issue you are having .

Weasel,

I hear ya, i was thinking about this too. My Evo doesn't have variable Cam timing, but my Honda (years ago) did, yet it would "crossover" at 5500rpms, does the Vanos change earlier, is it driver dependent, or does it change at a specified RPM, like the Honda. The "Vanos" and "3.0 Engine" articles are dead in the tech forum so i apologize about the question.

-Jon

It is more computer controlled by inputs etc., not at a set rpm like honda.

Also, see if you can tell if it feels like the engine is the cause of the studder, or if it feels like it could be possibly by the x-drive case messing with the clutches... I've seen that on a few x-drive E53's, could happen with the E83 as well.

Weasel, i hear ya, i have had the x-drive act up at a partial acceleration as well as turning the vehicle. It does feel the slightly different.

Today i burned through all the gas (or nearly all) had the "---" readout, put in 93 and a fuel cleaner and seems to be running a little better. On a scarier note i also need to add oil to it is as well which might impact the VANOS if it is a "oil based" actuator and might have been starved. I couldn't believe it was a quart or two low, but we'll see.

Thanks for the help guys and i'll keep you posted.

-Jon

your car is using oil
fuel cleaner improves running
this happened to my 740i , the crankcase breather diaphragm was burst allowing intake to draw oil .
could be yours is drawing oil , causing havoc with intake system .