You are right in assuming that "red-lining" means to drive fast. Red-lining it just means he had the speedometer (or the tachometer/RPMs in a manual transmission) as high as it would go, in the 'red zone', pushing his truck to its limits in order to get to Ennis as fast as possible.
Yup, I understand — thanks!
The person who have written those word-to-word translations I got here, when asked about it, told me: "NO, it doesn't mean "to drive fast". First, because of the word
it (to red-line
it). In this case it means that
it stayed in his mind, he could think of nothing except
getting into this again. And second, there's the following phrase which dublicates the first one: "...I red-lined it all the way.
I couldn't get here fast enough."
So considering what
coffeedrinkintexan has said, Jack, saying I red-lined
it, doesn't mean anything special, there's no any reason of adding this word (
it). It just means he drove very fast, as fast as possible.
So closing this question up, here's my rephrasing and understanding of what Jack is saying:
"I didn't know we was going to get into this again. No, I guess, [in fact] I did [know]. I drove as fast as possible. And I couldn't wait till I finally come to you; waiting was excruciating; poignant; anguished (from the dictionary) /=waiting was terrible for me/If everything's right, I'll be just happy!
I admire your desire to get it all right!
Thank you very much! But I always feel I'm too meticulous (hope that's a proper word — or, maybe, captious?); I feel awkward a bit, asking one question two or even three times. That is why I really appreciate your help! You spend your time helping me.