Reduced engine power...what causes this? Tune?
 

I was driving down the road after driving all morning and my car started violently shaking and I could only get up to about 10mph. Every light came on the dash. I pulled over and let the car sit and then it started up fine. Now I have a CEL code P2135. I've had an SS 4 years before my ZL1 and never had this happen. I just recently got a email tune from Steve at RDP. That's the only thing I've done differently. Should I flash back to stock? Any help is appreciated. Thanks.

P2135 has something to do with your throttle plate position to the signal it's sending to the PCM. It's a starting point.

Either throttle body or accelerator pedal position sensor

Do you have a VTC? that usually causes that

What the P2135 code means. This particular trouble code indicates that the Power Control Module (PCM) has detected an erroneous reading regarding the voltages transmitted by throttle position sensor A or B, the accelerator pedal position sensor and or the actual throttle plate. A ported throttle body or one of those Vitesse units could cause this.

I dont have either a ported throttle body or whatever this vitesse thing is. The only thing done differently was the email tune I got from Steve at RDP. Could any of the parameters that get tuned cause this? I'm afraid to drive the car in the event that this will happen on a highway. Thanks guys

I would reach out to Steve directly, he's usually pretty helpful for troubleshooting.

I assume the tune flashed without any problems?

Edit: I see Steve is already on it. I'm sure you guys will figure it out.

Try removing and cleaning the throttle body and mag sensor. It is a known problem on gm vehicles and I had success doing it. The carbon buildup is not much but messes with tps.

Be sure to check the wires going into the throttle body. These cars are notorious for having issues in the harness at that location

^^^this. I had the same issue and gradually got worse, enough to the point where it happened 90% of the time leaving work. After some research, I ended up replacing the throttle body and accelerator pedal. The problem never came back. It has something to do with one not being able to communicate with the other, which puts your car into limp mode. You can find a way to troubleshoot whichever part need to be replaced but both were cheap enough on eBay that I didn't bother with narrowing it down.

Solid advice from over the years..... its the throttle body needing cleaned tightened etc...or even more likely the Pedal assembly which has the dang potentiometer in it that limits the power by delay with drive by wire.... and others have had to replace one or the other.