Bumpy acceleration
 

So I've done my searching, please let me know if I missed the big thread on this. Since I bought my 2017 SS 1LE 6M I've been unhappy with the throttle on the street. Not just the lag, I fixed that with a Soler TB and controller. Great product (I like CF-4 for daily), I can dial in the mapping easy and I love the increased low-end response but it didn't fix the inaccuracy of throttle position.

The car is a joy on the track, so smooth and does exactly what I want. Spirited driving on the street feels great. However, I can't drive that way all the time. Shallow throttle and maintenance throttle between 1500-300 rpm at <20% produces bumpy acceleration. It will hesitate and wabble (like you're tap dancing on the pedal). This is not that A8 TC issue, this is not a cold start or slip/traction issue. It happens randomly any time, TC on or off, even with the "long hold" TC/SC off.

Now, I have had intermittent problems with the camshaft sensor CEL, but this throttle issue occurs so often, without throwing a code for weeks on end, that I have a problem blaming that. Plus, I don't want to remove my TB/controller to take it back to the dealer.

I'm about to buy an new OE throttle pedal from Rock Auto to continue my process of elimination, but figured I'd post here first. - Thanks for any advice.

Assuming that this happens even in track mode whose throttle mapping is the only one resembling a linear curve, I'd first data log the issue with HP Tuners and look at all the associated channels (pedal position, commanded throttle actuator, SAE throttle position etc.) to see where this jerkiness may be coming from.

If the position sensor value varies while you're keeping your foot in the same position, switching out the pedal assembly may help.

No other ideas apart from this, hopefully someone else can also chime in to help. Good luck :smoking:

Thanks, it seems to do that. I feel like my foot is static on the pedal with slight pressure, and it's slowly coming up through the lower revs, when it bobbles for no reason. Probably would be good to get a log of the throttle response to the pedal action to see if there are any spikes or dropouts, but I think that would just bring me back to the pedal assembly anyway.

This isn't the car I'm supposed to be working on, I have the LS3 arriving next week for my C5 swap! :happyanim:

Let me know if you have trouble sourcing a new pedal assy, I have a spare lying around in perfect condition.

So I installed a new accelerator pedal, no difference. It seems so random, at times I'll do a whole commute without it happening, then it will happen 5 times in 2 minutes. It dips down for no reason, blips up for no reason. Not dangerous or anything, it's over so fast that it's just an annoyance, but man I hate being surprised by what my car does. It's all the more frustrating because I love everything else about this car.

I'll have to get some logging saved out to figure out what's going on. Never used the HPTuners stuff but want to look into it.

You need to pinpoint the item that is causing the problem, Start with taking the Throttle Controller off. Still there, put the stock TB back on, still there then it's time to go to the dealership.

There were some people having surging issues with the ported TB and Soler was pretty good about working to fix the problem with them. Maybe you have that problem too, just a thought.

Thanks Scargoes, that's my plan, kept the OE TB for that reason. Just might take a while to get there so looking for any other tidbit of wisdom that could be the silver bullet I'm looking for.