Thank you for the replies, so far.

I'm not sure what a CPS is. I don't have a code checking device, and the check engine light is not on. It's an automatic transmission, by the way.

I've had the car for only two years and, frankly, never brought the RPMs up very high until after having the tune up performed, and after the Seafoam. I put only about 1,500 miles a year on it.

I used to buy used cars frequently when I was young and enjoyed repairing them. But that was a long time ago. All the fairly recent cars are half car and half computer, so I gave up on doing-it-myself. This is only the second used car I've purchased in the last twenty years. And yes, I'm positive the mileage is accurate (~13,000 miles).

I want to reiterate the fact that it runs great in every way (starting, idling, gas consumption, etc.) except when I floor it and take it up to 4-5,000 RPM, when it sometimes (not always) cuts out completely...sort of like I took my foot all the way off the gas. I've already had the repair shop, which I trust, make sure the work they performed was done properly.

This is the only car I've ever bought strictly because I love the way it looks. It has beautiful lines, from every angle. Looks better than much more expensive cars, in my opinion.

Anyway, I'm guessing that even if this problem does not improve, the car won't leave me stranded or even detract very much from my enjoyment of it. Looking back, I realize I should have been driving it in a more "spirited" way, to keep the engine and fuel areas from becoming clogged. It's just that it runs so well except for the intermittent problem described.