When Mulder and Crump are coming down the hill where Scully is waiting, both driver's side windows are rolled down. But when Mulder stops and Scully runs up to the car Crump's window is rolled up.
Many of Scully's actions at various times are inconsistent with her training both as a criminal investigator and a medical doctor. For example, she can often be seen handling potentially contaminated items, and even performing autopsies, without gloves. (This sort of thing is particularly noticeable in episode #6.2, "Drive", when she is poking around inside the dead woman's head.)
At night when Crump says, "faster" we see the odometer reads 4057 then an obscured number. the next morning the odometer reads 40613. This is a maximum increase of only 43 miles during which time we have traveled from pitch darkness to broad daylight. At a speed of at least 70mph, daybreak has appeared in less than 35minutes.
As Scully walks into the Crumps yard and her flashlight illuminates an old chaise longue, a person wearing a white tank top runs out from the bushes and off screen to the right. No reference to this person is made in the story.
During the opening scene when we see the woman in the police car from the perspective of the news channel helicopter, an air cannon used to explode fake blood onto the car window can be seen between the two front car seats.
(From 15:20 to 15:30) You can see camera equipment that was revealed during the show's transition from 4:3 to 16:9
After about 15 minutes, during the scene in which Crump tosses out Mulder's cellphone while being chased by police, as Mulder says: "How about if we just pull over and let me out, too, huh? I must be cramping your style" something looking like camera equipment (probably filming the shots with Crump in the backseat) is visible, actually blocking what little view we have of Crump pointing his gun at Mulder.
The most fuel efficient version of the 1968 Chevy Caprice had a 24 gallon tank and is rated by the EPA as getting 10 miles per gallon. That puts the maximum range of the vehicle at 240 miles on a single tank of gas. Highway 36, as it winds through the mountains of California from Susanville to Hydesville, is 243 miles long. As the crow flies, Susanville is still over 30 miles from the Nevada border while Hydesville is still more than 10 miles from the coast. At the 80+ miles per hour speeds depicted in this episode, there is no way that vehicle could have made it from the Nevada state line to the coast on a single tank of gas.