This problem sounds kinda familiar, but it might help to know more about it.
I would suggest that, if you haven't done so already, then it might save some time to identify the problem more precisely. Just look simply at a couple of those those tracks that consistently display sound artefacts when played on the car's audio system. If they consistently display the same artefacts when played from the same USB stick, but on another player, then you will have probably correctly identified the problem (corrupted data), but not its cause.
If otherwise though:
(a) Can you also hear the artefacts when the radio is on and whilst the car is being driven and the engine is running?
(b) Do the artefacts when playing the mp3s only occur whilst the car is being driven and the engine is running?
In either case, then, from experience (and if it's a conventional gasoline-powered vehicle), I would suggest that you check over the condition of the car's ignition system, in particular the HT leads. If the sparkplug leads are invisibly breaking down (end-of-life) or have old suppressors (which could be invisibly failing), then there'd likely be a lot of strong bursts of electo-magnetic radiation going on under the hood due to sporadic HT arcing. This radiation could usually cause interference on the car radio aerial or any unshielded audio wires and would typically come out variously as a regular "ticking" sound, or intermittent pops, crackles or "whizzing" sounds.
The same thing could happen if the spark plug insulators are failing (like the HT leads and suppressors, they don't last forever, but plugs do need to be periodically replaced, whereas HT lines tend to last longer and thus get overlooked), or it might just be that the spark plug gap has not been checked at relevant service intervals for a long time and has worn too wide and now needs to be reset to its correct gap for that plug+vehicle. In the latter case, once the plug gaps are set correctly and assuming the plugs and HT leads etc. are otherwise OK, then your engine will probably run smoother and get some power back.
Just some thoughts.