I just did a quick search, but one source mentioned that the MR20DE engine has mechanical valve lash. I have no idea if lash adjustment is done by replacing cam lifter bucket(s) with the correct the OAL, like a Toyota 2AZ-FE, or if it uses shim under bucket adjustment. Either way involves pulling camshafts if a prior proper clearance check shows the need. There's always the chance it could also be a noisy VVT solenoid. At 120k, either item could be needed.