Engine Power is Reduced, Traverse 2010
 

Recently I got Engine power reduced message on the dash of my car when I checked the codes it was P0087, P0089, I changed the high fuel pressure pump which is attached to the engine with a new one and also I changed the fuel rail sensor.

After that car again given the same message, this time I checked the codes and it says "pending faults P0087 and P050A" with a warning sign.

Then I cleaned the fuel injections but the problem does not resolve. lastly, I changed the throttle body and cleared the codes. However, all this goes in vain as the problem is still pending.
Can someone please help me why this message of "engine power is reduced" as soon as I start the car and after a few seconds the same message with three DING DING DING sounds.

I even tried to disconnect the battery for 1 day but nothing changed.
On the cold start car idle roughly with a couple of misfires in multiple cylinders however after idle it runs with reduced power and barely any misfires in cylinders.
I cleared codes after each part changed with the obd2 Bluetooth device on my android phone. :(



https://youtu.be/9iO7i2TaCXM​ ​​​



https://www.gmtruckclub.com/d2/attac...54a1735071.jpg
https://cimg2.ibsrv.net/gimg/chevrol...9bcbb3bf6.jpeg

Today I checked the car again, If I Switch on and do not start the car, the throttle body changes its position and returns to start position which is I believe normal. However, I found clicking sound from the High-pressure pump If I pull off it's connected the sound goes away. I connect this connector to my old high-pressure pump but even on that, I was hearing this clicking sound. It just like a pulse of a short circuit.

I check its wiring everything looks normal no shortage until ECM.
still, my car is showing reduced engine power any ideas or help will be appreciated.

Those faults you are seeing are pointing to low fuel pressure at the fuel rail, which matches the engine running poorly. The high pressure pump needs to have the correct pressure from the tank to work properly. If you have a replaceable fuel filter I would start there, but otherwise you will need to check the fuel pressures with either a gauge or scan tool to see what is going on.

Did you ever figure out what was wrong?