Mr. Monk Gets Stuck in Traffic - S3-E13
Factual error: Monk inspects the wrecked VW Beetle and notes that "the air conditioning is off." But it's a standard 1973 VW: they didn't come with A/C, and though you could add it, it tended to overstress the little air-cooled engine. Look closely and you can see that this VW does not have the bulky under-dash compressor needed to run an add-on A/C.
Mr. Monk Gets Cabin Fever - S3-E12
Factual error: Randy calls the cabin and gets a "not in service" message. But he should have heard an unanswered ring instead. The FBI agent tore the cord from the wall, which in the US does not generate a "not in service" recording. That only occurs when the phone company cuts off your service due to non-payment or cancellation. (00:30:00)
Factual error: As Monk is removing the crumbs off the keyboard, he flicks one crumb away from the backspace key. It gets flicked up and lands near the 0 button on the numeric keypad. Yet when this happens, the screen then says "Do you want to delete files?" as if he hit the delete button.
Mr. Monk Takes Manhattan - S3-E1
Factual error: The .22 caliber shots would be a higher pitch.
Mr. Monk Takes His Medicine - S3-E9
Factual error: The medication Monk is given is called Doxinyl, which is a real medication, but it's an antibiotic, nothing to do with OCD and certainly wouldn't cause the side effects shown.
Mr. Monk and the Panic Room - S3-E2
Factual error: The cops gain entry to the panic room to be faced with a chimp waving around a loaded handgun, apparently having shot a man, and shrug and make jokes about reading him his rights, instead of expressing the slightest concern that this animal might shoot them. Cops shoot remotely aggressive dogs all the time, but an ape with a gun doesn't even make them raise an eyebrow. Plus the police never did a gunshot residue test on the chimp. Standard procedure, and would've proven they didn't shoot.
Mr. Monk Takes Manhattan - S3-E1
Factual error: In the episode the victims were murdered with a .22 caliber firearm. However, a short shot of the crime scene focuses on an empty shell casing which comes from a larger caliber firearm, most likely a 9mm parabellum. (00:05:30)
Answer: Notice also that in the opening credits scene when he is touching parking meters her also wipes his hand on his clothes each time he does it.