Guy's help me sort this before I sell the bike.

[fouramdesigns]

Had some issues with the CO/fuel. Took the bike to the local Ducati dealership, said it was off, and the throttle bodies were out of synch. Also, the chain was loose as they just replaced it in February. I picked up the bike last Friday, had the clutch issue. Problem solved. Fast forward:

Installed 2 new NGK R plugs, correct part/ Seemed to be running like a champ. But, even before I changed out the plugs, it seemed to be missing that whipping neck feel. Almost there, but not there. Follow me?
I rode the bike 400 miles from Nashville to Jackson, Miss. Bike seemed to be running fine, but I was loaded down with a back pack, and on the interstate, so I couldn't play around. Filled it up 3 times on the ride down.
Went out for a quick ride tonight, gas light comes on, I stop, fill it up. I romped on it a bit on the way home. Feels like it's lagging just a hair. I didn't ride the bike for almost 3 weeks. But I was thinking to myself. Maybe I've gotten use to the bike.
That thrill in the seat just seems to be missing. I even wondered with all this Ethanol in gas, if maybe that's the issue. I had the belts replaced, but not the valves adjusted. What are the chances that the work the Ducati shop did has changed again?
I mean what would cause the CO/fuel system etc to keep changing itself? I still smell gas in the exhaust, and had one backfire on the way down from Nashville. Also had one pop in the throttle body. I just want this bike fixed, and not be the money pit it is becoming. I'm not raw hiding the thing to death.

[hypurone]

Well hell, I'll go first! 

For starters I would check the condition of the air filter, replace/clean as needed.

Then, circle back with the shop to verify the cam timing is correct (after belt change) & reset the TPS & CO once more.

Run thru a tank with some high quality fuel cleaner in it (seafoam, JB or the like)

That being sorted and if you still have issues. I would look to the air temp and coolant temp sensors as these are the major "input" values for the ECU to compute the "mix".

[fouramdesigns]

Thanks for your reply. I just cleaned the BMC a few weeks back. I will pick up some cleaner and try that. When I get back, I'll take it back to the shop. They should recheck it since they completed the work, right?
The Sea-Foam can go right in the tank?

[DucHead]

Seems like too many problems for a new bike, although it happens often with the 1st generation of a new model.  It's under warranty, no?  Take it to the dealer and have them make it right.

[Speeddog]

Could be a fuel filter issue.
Or, fuel lines in the tank.

Those can make the running quality change at a quick rate.

Both of those would make it go lean, though, so likely not the issue from your description of how it's running.

Could be a cam timing issue, or a belt tension issue.
Both of those can be checked by removing the belt covers, which is pretty easy.
Well, getting the middle cover off is a bit of a 'zen puzzle'.

BTW, which plugs did you put in?
And how do they look now?

[fouramdesigns]

it's an 01' S4. I may just buy a new 848 or 696. Still trying to decide.

[fouramdesigns]

Could be a fuel filter issue.
Or, fuel lines in the tank.

Those can make the running quality change at a quick rate.

Both of those would make it go lean, though, so likely not the issue from your description of how it's running.

Could be a cam timing issue, or a belt tension issue.
Both of those can be checked by removing the belt covers, which is pretty easy.
Well, getting the middle cover off is a bit of a 'zen puzzle'.

BTW, which plugs did you put in?
And how do they look now?

I've had the belt cover off, belts looked tight. I put the NGK R plugs in. Like I said, bike seemed to be running great, till on the way home. Can you fill up the tank too much and cause I sensor to trip? I filled almost to the top. What about Ethanol? I've heard some rumblings about the additive.

[Speeddog]

Specifically, which plugs?

Could be the ethanol, could you switch to a known non-ethanol fuel?

Belts looking tight and being properly tight are 2 different things.
Cam timing could be off.

If the bike still has the emissions canister, overfilling can cause running issues, but not likely across the whole powerband.

[fouramdesigns]

Specifically, which plugs?

Could be the ethanol, could you switch to a known non-ethanol fuel?

Belts looking tight and being properly tight are 2 different things.
Cam timing could be off.

If the bike still has the emissions canister, overfilling can cause running issues, but not likely across the whole powerband.

NGK DCPR8E. The canister has been removed as far as I can tell. Would be near the rear panels correct?

[Speeddog]

Proper plugs for S4:

Denso Iridium IXU27
Champion RA59GC

NGK doesn't make a correct plug AFAIK, but if I had to use one, it's be a DCPR9E, but I haven't tried it, so YMMV.

[♣ McKraut ♣]

i'm using the DCPR8E in my s4r....though mine is popping like mad.  maybe i need to score some different plugs and try that out.  would the Denso Iridium IXU27 or Champion RA59GC be appropriate for the s4r as well?

[fouramdesigns]

Proper plugs for S4:

Denso Iridium IXU27
Champion RA59GC

NGK doesn't make a correct plug AFAIK, but if I had to use one, it's be a DCPR9E, but I haven't tried it, so YMMV.

Where can I score some online? None available locally.

Champions site: http://www.championsparkplugs.com/results_appOther.asp?otherMotiveID=15101&mfid=2 Not the same model number as you mentioned

[Speeddog]

Not sure of an online source.

Make sure the Denso have the removable terminal, S4 coils require just the threaded nub.

You should be able to get the Champions from Ducati Seattle, kinda pricey the last I checked. 

[fouramdesigns]

I added a link to the Champion plugs. So what's the difference?

[Speeddog]

I'm not sure what the difference is between the Champion and Denso.

I've had good luck with the Champions in my S4.