Sounds like a flat tire.....

[Interceptor]

On my way home last night driving down the freeway at about 70 MPH and all of a sudden I hear what sounds like a flat tire... (ca-thump.. ca-thump.. ca-thump). I pulled over and to my surprise all 4 tires look just fine!
The sound gets faster and slower with speed and starts at about 30 MPH.

I've ruled out anything to do with the engine.
My first fear was a wheel bearing had packed up, but with some research I think I may have found the problem. The symptoms sure sound like it could be a tire "de-lamination" where the tire layers separate internally.

BTW: I'm running Goodyear Tires EAGLE RS-A.

[Nazrom]

Depending on how much tread life you have left on them, might be a good time to change them out anyway. I change mine out every six months just to be safe.

[Interceptor]

I still have *enough* tread on them. I just don't have the money to replace any tires right now, but thank goodness for the full-sized spare.... even though that tire already has a plugged hole in it.
I would rather have to pump up my tire every few days then have one explode on me while driving 70+MPH!

[Jake]

The symptoms sure sound like it could be a tire "de-lamination" where the tire layers separate internally.
BTW: I'm running Goodyear Tires EAGLE RS-A.

I had the same problem a couple of weeks ago which prompted my purchase of the Michelins.

I saved the old tire. It now sits in my garage with about a 1.5" dimple in the thread area.

[Pecos Slick]

Try to take it to a Good Year dealer and see if they will make an adjustment.

[davorocksL67]

my regal had eagle rs-a's from the factory, at >40k miles it had the same issue. i didnt beleive the dealer, he told me replace the tires and if he was wrong he would pay for the tires. he was right.

[Pecos Slick]

I just acquired 4 RSA+s two with 8/32 tread. If I had a cheap way to get one to you I'ld let you have one.

[Sunfish]

Many times a tire will separate from a improper repair. Never just use a rubber plug always put a radial patch plug (peter plug) in from the inside and use good cement. On the bigger holes use a carbide cutter to remove the steel from the puncture hole. The reason being you are trying to prevent the steel from rusting inside the tire. Once the steel starts to rust the thump,thump,thump is not far behind. Sunfish