Hesitation problem

[Slickhorn]

I searched but couldn't find any threads specific to my symptoms, if I missed one, please point me the way.  For background I have a '99 885i with just a tad over 62,000 miles.  She's always run like a champ and other than a minor oil leak or two I've only dealt with normal maintenance thus far...  I did a problem free 4000 mile trip this spring and then last week after an oil change and a clean-up took her out to enjoy the scenery above home. 



The dirt roads were a little rough in spots from the melting snow but no major obstacles.  As usual she ran great through about 60 miles of backroads but when I hit the pavement to head home the trouble started.  As I pulled away from the stop sign she died (in traffic no less  ) but started right up and off we went....then the real trouble started, hesitation on acceleration, some sputtering and no power at top end.  I could barley get up to highway speeds and then it would slowly lose power.  So I limped home and tore into the bike, with any number of possible problems in my head...most likely a fuel problem of some sort.  After removing the tank, I found this:





So I thought it was going to be as simple as the throttle cable being replaced.  Finally got the new one and threw it together, the slow bleed off of power is gone, but the hesitation remains and the sputtering.  She idles perfectly, sounds good but just doesn't want to perform on acceleration, I feel like i'm dragging an anchor on the road as well.  Checked for a dragging brake and bent axle and neither appear to be the problem so where do I look next?  Throttle bodies?  Clogged injector?  ECU bad??

Thanks in advance for any wisdom

[NortonCharlie]

My 1st guess might be a fuel pressure problem, maybe a fuel filter?  Having a smooth idle I think rules out a clogged injector.  I imagine you looked over the air filter when you had the tank off.  Maybe just picked up some bad gas.

I suppose it might be throttle position offset, but that really should reset itself with a couple no throttle start ups accompanied by a minutes idle.

[John Stenhouse]

Vacumn tubes check they aren't split and the IACV valve cycles when it should

[Sin_Tiger]

  Since the Guru's seem to be in meditation or out riding, check those for cracks / poor connections.

Then it's the "adaptive tune", not sure how applicable that is to the 885i.

[Bixxer Bob]

"Tune" depends on whether it's got an O2 sensor.  If it has it's the "Adaptation" if not it's the 12 Minute Tune.  Once you've checked you haven't introduced an airleak or something while you were working on it, do that first.  Then run it to see if it's any better.  If not, then I'd reset the TPS because it's probably trimmed itself for the butterflys not being properly closed with that broken adjuster.  Be careful to warm her up properly first or you'll have a pig of a job starting it.

Once the TPS is reset, balance the TBs.  Then - as long as it's pulling strongly - do some miles.  It'll eventually trim itself back to where it needs to be.

[Sin_Tiger]

  Thank Gawd for that, thought you were never getting here, stuck in traffic or what  I can go back to my pig pen now.

Nice looking bike now that I can see the pics.