[BGCarrera32]

Depending on if you are specifically referring to the pressure damper on the passenger side injector rail, or the pressure regulator on the driver's side rail (or both), beyond poor running you can have:

1) hard restarts as the pressure in the system isn't holding but leaking down because the regulator is shot and can't hold pressure

2) different AFR readings on the right bank vs. the left bank

Step 1 is to attach a pressure gauge to the fitting on the driver's side rail to check operating pressure and leakdown pressure over time after the engine is shut off.