When to get a loan?

I am brand new to the whole care buying experience having just graduated from college.

Right now I am searching for the perfect car. I have exactly what I want in mind, but it is very specific, so there aren't that many around (looking at a used car).

I am not in dire need of a new car, so I plan to wait until what I want pops up. However, I think I will need to jump on it quickly when it does pop up. I am looking all over the place: ebay, private listings, online dealers, classifieds, local dealers, etc.

Here is my dilemma: I am going to need to get a loan for the car I want. I do not want to have aquiring a loan slow me down when I find the car I want, but I also do not want to have a loan sitting around for a car I dont even have (nor do I know if the bank will even lend me the money without a specific car ready to purchase). I may find the car I want tomorrow, I may find it in 6 months, I just don't know.

Is there anything I can do? Should I get quotes from banks ahead of time and then let them know when I am ready to move? I think most rate quotes are only good for a week, and if they are pinging my credit every time they do a lookup, that is no good.

Should I try to talk whoever is selling it into giving me a couple days while I secure financing? This makes sense to me, although they may not do it, and if it is something like an ebay car or something listed multiple places, they have no reason to hold it for me. If its there when I come back, great, if not, oh well.

Any insights?

Check with your financial institution to see how long a rate or terms are good for if you get "pre-approved" for a loan. Some may have different lengths of time, but since there are so many issues going on now in the economy regarding the issuance of credit and situations can change very quickly on both ends, many may not elect to keep the same time periods as they did in the past. I would venture a guess to say credit unions might have a "longer" period of time where the rate and term are good for.
As for the "pinging" of your credit file, I understand that has changed within the past couple of years to give the consumer a "window of time" to look at credit options before it has an impact on your credit score. Here is something I found to substantiate this statement from a website www.thesimpledollar.com:
"Another tip: if you’re shopping around for a mortgage or an auto loan, don’t worry about hard pulls. According to Trans Union, the FICO model accounts for this:

You can still shop around for a loan; multiple inquiries for the same purpose in a short amount of time are commonly grouped into one less harmful inquiry session. Inquiries are also helpful for consumers because they can notify you of a potential identity thief applying for accounts in your name.

In general, you shouldn’t worry too much about the occasional hard pull, especially if you don’t have any major loans coming up. The “cost” of a hard pull is slight on your credit score, often not nearly enough to impact anything. You should only worry if you’re applying for a bunch of different kinds of credit very quickly or if you are looking at a major loan in the near future."
This is good for people who like to shop around for the best rate. I found out about this 2 years ago while looking to refinance my mortgage. I believe for auto loans they use a 14 day window, and for mortgages they can go up to 45 days.
Your best bet would be to see what financing options suit you the best and talk to those involved, (i.e.credit officer/loan manager) as to your intentions so they are aware of what you are trying to do, and it can be easy "at a moments notice" to help you get the financing for your purchase.