Ok listen to this - from Nurmi's questioning Jodi about the gas cans and her bizarre behavior:
http://www.youtube.com/watch?feature=player_detailpage&v=3tP_lXQcVbQ#t=1055s
Nurmi asks her why she chose to fill up at the pump on her way in to Mesa instead of using the gas that she had filed the extra cans with -- remember she said she filled up in Desert Center and again in Buckeye.
Listen to Jodi's answer -- she cannot remember which lie she's supposed to be telling because she gives an answer that has nothing at all to do with her trip to Mesa or why she filled up on the way. She gives an explanation about not knowing the route through Nevada on I-15 to Utah, and that she wanted to fill up her car first, rather than use the tanks because she was unfamiliar with those roads.
But that's not the route she took -- that was her alibi route when she was maintaining that she was never in Mesa. She took I-10 to Mesa which she had driven many times before, so her explanation based on a fictitious road trip from Pasadena to Utah does not have any bearing on what she actually did on her real murder route from Pasadena to Mesa.
She did not get gas in Desert Center or Buckeye - but rather than come up with a plausible lie to explain why she might have stopped in those places to get gas, she cannot remember which lie she is supposed to be telling -- so she veers off into the outdated "I was never there" lie and tells a lie within that context.
I do not know if this was pointed out or discussed by Juan - Nurmi just glossed right over it, maybe because he knows his client must be lying and there's nothing he can do about it after the wrong lie escaped her lips.