I was thinking that too!~
We actually don't NEED to buy a car before the house, was just trying to figure out if it is better to show we have some debt that we are paying off each month, or is it good enough to see that we had debt that we always paid on time and paid off. WE have had 2 houses, a few cars and student loans that we always paid on time and finally paid off. DH is really good with money and keeps me in check!
Your high credit score already reflects that you have the ability to pay your credit on time. So, it reallly isn't necessary to have outstanding balances right now....even if you pay them off each month, you probably still have a balance at the time the creditor reports to the bureaus. So, the mortgage company won't know that you're paying them off each month, anyways (Unless you provided the statements which isn't necessary)
It's best to wait until closing to shop for a car. Often times your credit will be "shopped" around for competitive rates. This could put a half dozen inquiries on each credit bureau within a 10 minute period!
A new installment account, new inquiries, etc WILL drop your FICO scores (how many points depends on how thin your file is) which affects lending rates. It takes several months to recover those temporarily lost FICO points.
As far as I know, the only lenders that will "shop" your credit are BROKERS. Try to stay away from brokers and try to stay with a mortgage company that is owned by a bank. The way to find out if you're dealing with a bank owned mortgage company vs a broker is to ask if they are a Direct Endorsement lender. If they are then they're a bank owned mortgage company. If they aren't then they're a broker. Or to be safe you could just go to the bank where you have your checking/savings account(s) at.
The statement about new loans/inquiries dropping your FICO scores immediately and then take months to recover is most definitely true!
It's easier to qualify for a car loan than a mortgage loan, so I would definitely shop for a car AFTER you buy your house.
Also, I work for a bank owned mortgage company and I've never heard the rule of thumb of waiting 6 months after buying a house to apply for new credit.

Once you apply for a mortgage you definitely shouldn't do anything (apply for credit, use any open credit cards, etc.) until the day after you close. We are required to pull a "soft" credit report within 48 hours of closing. That means we re-check to see if you have any new debt. It does not show as an inquiry on your credit report because it is a "soft" report.
Hope this all helps and makes sense!!
GOOD LUCK HOUSE HUNTING and then CAR SHOPPING!!!
