While driving yesterday my engine light came on and my truck misfired a time or two. I stopped checked oil level and pressure, all was good. The new K&n air filter had fallen off so I put it back on. Engine light still on but no misfires. Went to auto zone for a diagnostic and got a P3400 code cylinder deactivation bank 1 replace oil manifold lifters. The truck is a 2013 with only 43k miles. Shouldn’t be having this issue already. After further investigation I found the MAF sensor on the new cold air intake was loose. I tightened it down and reset the code. Drove this morning and it didn’t come back on. Truck actively deactivates from v8 to v4 for fuel economy as it should. Oil levels good, no knock, shaking or misfires. Could the loose MAF sensor have been the issue?