07 Avalanche 5.3 Vortec flashing p0300

Hi I have a 07 Avalanche 5.3 vortec with a flashing p0300 and p0351 took it to dealer and they said it was the heads a month after problem was the same they end up replacing engine a year after when warranty was over problem came back I just had the DOD/AFM delete change injectors ,lifters,valve springs,a none DOD cam plugs, wires ,coils ,throttle body, and the flashing p0300 and p0351,traction stability light on and the problem still there ,it starts flashing at idle only when I step on gas it seems fine it has some power and it goes to regular speed new engine only has about 63,000 miles
It seams like bank 1 not working

Everyone that I ask doesn't seem to find the problem one mechanic told me that it has no compression
I really don't have the money to spend and keep changing parts I haven't found a job in 5 months I'm a truck driver but I been checking your videos to try to figure out the problem but lost

Marlon, we're happy to help! But we need some more info first.

What kind of tooling and test equipment do you have available? Test light, multimeter, scan tool? Compression gauge?

What testing have YOU done so far? Not what the dealer or anyone else says.

Does the P0351 always set with the P0300? Put another way, if you clear the codes and start the engine, do both codes return? Please, be clear about this. The presence of the P0351 means going in a completely different diagnostic direction.

Hi thank you for replying back I used a compression tester and I got this results
1# 130
2# 180
3# 120
4# 160
5# 170
6# 170
7# 180
8# 175
I did it myself I can't get anybody that wants to check it out