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Q: I was under the impression that all states must have highway exit numbers that are milepost-based. I know several New England states have had to renumber their exits. I would like to get a new road atlas for my husband once all the states adhere to this. I don't want to purchase a new atlas, only to find out that additional states still need to make changes. Do you know if or when this project might be completed?
A: The Federal Highway Administration (FHWA) dictates how exit sign numbers should work. The operative word here is "should." Some states have not gotten around to complying with the directive. Unless the old atlas has worn out, stick with it and save a few dollars.

Oh, nuts

Q: I have a 2017 Ford F150 with 40,000 miles. I took it to the dealer I bought it from and asked to have the tires rotated, which this dealer — and only this dealer — had done five times before. I was told that I had swollen lug nuts. They said they would not remove them unless I paid for replacement lug nuts. They basically claimed the original nuts were defective, but neither Ford nor the dealer would stand behind them. They offered to replace the 24 nuts for $70 using aftermarket parts. What's up with this?
A: Ford has long suffered with this problem. There is no cure but to replace them. The original ones swell when moisture and brine get between the lug nut and its chrome cover, causing corrosion. During removal the nuts are destroyed and cannot be reused. Aftermarket nuts are fine and cost less than new ones.

Rotation issues

Q: I balked at paying the dealer to rotate my tires during an oil change. I was told that there is no fee if you buy the tires from the dealer. I replied that I had, indeed, bought the tires from them — when I bought the car. They finally said, "We will make an exception for you this time." I did that with both cars when they were new. Since then, we have bought replacement tires from a national franchise tire company that has free rotation and flat repair.
A: I like your moxie. I am surprised when a shop charges for tire rotation. There's also an upside for the shop, including a chance to inspect the brakes and potentially get additional service work.

Idle thoughts

Q: A question on the discussion of why idle rpm is higher for a cold start: Isn't the high idle speed (and secondary air injection) programmed to more quickly heat the catalytic converter to its optimum temperature?
A: Yes, but the science of fuel having trouble vaporizing effectively in a cold engine still applies, too.

Bob Weber is a writer, mechanic and ASE-certified Master Automobile Technician. His writing has appeared in automotive trade publications, Consumer Guide and Consumers Digest. Send automotive questions along with name and town to