Slight Transmission/engine Rumble

[DFGeneer]

Hello guys

I am asking you for advice.

My Lex is 1999 IS200 with manual gearbox and about 165000 km on the clock. Last service done on 157000 km, including engine, gearbox and differential oil change.

Recently it started to develop slightly noticeable rumble when the torque is propagating from the wheels to the engine, i.e. car already moving and suddenly I step off the throttle. In an instance, stepping off the throttle feels like a bang (like engine stalling) followed by the rumble.

When throttle is pressed, even slightly, the car is very smooth.

In fact, the two issues appeared after geometry alignment, but probably that's just a coincidence.

A mechanic in a local garage advised be that the issue with the engine bang is probably due to dirty throttle body.

What do you think?