I knnoooowwww that this topic is over-used but I have an 'issue' that I didn't find anyone else had replicated in the million other threads about this, mostly because my car is fine, runing, driveable, just an annoying little problem has arisen since I completed this.

My car is an S4 N/A; only engine-related mods are a manifold-back exhaust with single, high-flow cat. and a K&N drop-in filter.

I followed the resistance method: Warm engine, unplug, ohmeter, adjust to 1k ohms, plug in, drive, repeat if nec.

My TPS was reading 1350 ohms but I've never had any idling issues, hesitation issues, backfiring issues, etc. with this new engine as of 2 years ago. I was simply doing this as a maintenance process and out of my own curiosity, since I've never checked it before.
So I adjusted the screw until I got it to 1000 ohms, then plugged it in and drove for a while, rechecked, and it had dropped to about 950. Re-adjusted, and it stayed at 1000 this time.

Improvements:
- no more big backfire when I let off from WOT at high rpm
- seems to be a smoother transition when letting off the throttle at mid-range rpm

Declinations:
- idle starts off very smooth, but eventually seems to get a little bit more erratic even though I'm able to keep it around 750rpm just fine
- a lot of small backfires at low rpm (below 2000) with little-to-no throttle, mostly noticed on engine deceleration.

Anyone know which direction I should head next?

 

After letting the car cool down completely, I started it (okay), let it warm up a little bit(less okay), then took it for a drive(not okay). As it was idling cold, it was bouncing up and down from about 1200-1500rpm. As I was driving, it got worse and worse to the point I had to barely limp it back around the block.
I reset the TPS back up to about 1200 ohms and it's back to work just about perfectly, with the exception of those little sputters at low rpm with no throttle, mostly during deceleration.
During the sweep from no throttle to WOT, the TPS goes from 1200 to about 5500, which is within spec.
I have a feeling if I reset back to the 1350 ohms tomorrow it would be back to normal but that shouldn't be. What should I check out next since the TPS should be closer to 1000 ohms at no throttle?

 

look up a thread called TPS Adjustment 101.
In the Sec Gen specific section.

 

That's the first place I went Dave! You should know I do my homework before I post something like this! haha
I have a feeling I've uncovered some other problem that was hiding behind the TPS, and now that I adjusted the resistance back into spec, it's shown itself.

+ I really don't want to take my throttle body off and start testing the thermowax and BAC blah blah blah. *If it ain't broke don't fix it* rings true in this case. Jeeeez

 

I have gotten to the point where I just needed a connector and cut it off of a good s4 tps.
I hate the plunger type tps's...!.sort of why I went with the FD type.FD Upper.

 

Sometimes the fast idle cam doesnt completely disengage. Take a screwdriver and push the cam away to ensure the tb closes completely (u may see it close just a bit more) and adjust tps while doing this. And this way u dont even have to have the car warm. Im sure lots of people adjust tps's with engines warm but with tb's actually not against idle stop...which is why u changing resistance is matching the tb's position and improving results.

 

My cure for this issue is to remove the tps, turn it the tps with the button facing down and spray the inside with wd-40. My theory is that sand and dust get in there and stop the button from releasing fast so the ecu doesn't send the right amount of gas to the injectors.

 

Wd40 is not really recommended for electrical contacts(poof.)..But Contact cleaner is..Go figure.

 

Gunna do some playing around with the throttle body when I get the chance... clean up the springs and linkage, do all the necessary testing and whatever else, maybe repaint the upper manifold in a nice original silver.

Do those dashpot actuator things on the front ever go bad? They are there to control deceleration when you throttle-off, correct?