And bare with me here...It's a lot to explain.
Ok...Doc got shot back to 1885 in his car. Marty then dug up the car in 1955, and went back to get Doc. Marty's car gets an arrow in the petrol tank and lose all the fuel!
Ok so far.
Doc and Marty try and fix Marty's car....But wait...Why don't they just use the feul from the Car Doc went back in time in.
Before you all flame me down think about it. In BTTF 2 we saw 2 time machines. The one they used to get back and try and fix the time line, and the car from the first film, in the scene where we see the 2 Docs, Remember?
So according to the BTTF law, there can be 2 time machines at the same time. So why doesn't this apply to the third film.
Doc went to 1885 in his car. Marty used the same car and went to 1885...so in 1885 there should be 2 cars.
The car that Doc got shot back in time in must still have had enough fuel for them to reach 88mph, but there was no mention of it whatsoever.
Also...The Lorraine thing. In 1885 we see a relative of Marty, Shamus..He's married to whatever her name is, who is played by Lea Thompson-who played Marty's Mum.
So in 1885 Marty's relative Shamus and some bird related in some way to Marty's mum hooked up, had kids and so on...But Hang on...That's just wrong. So it must mean Marty and his family from 1985 are in-bred somehow!
See... Fuck up!!!
Well you sort of get my point...Yeah??
There you go. Big fucking plot hole and IMO one big mistake that totally ruined a great set of films.
I tried my best to explain this, but it helps if you're stoned sitting here with me
BTTF 1 is one of my fave films BTW.