I can't believe it after thinking how dumb all the Toyota folks were. My 6 is an 05 4 cylinder with 63,000 miles. Friday I went on a short trip ( 50 miles)- and when I slowed down off cruise control approaching a town I noticed the car bucking.
I could easily hold the car back with the brakes, but I had to stop, and threw the trans into neutral. THe engine stayed between 2500 and 3000 RPM. It went up and down every few seconds...just as if I was blipping the throttle. I was closer to my destination and could control the engine- but I was nervous. I kept going and about 10 miles later it stopped acting up.
I had turned off the cruise control- no help- and lightly kept my foot on the throttle, but could not feel anything ...the gas pedal was not moving.

Today is Sunday, and it hasn't acted like that since.

I'm 64- got a lot of miles under the belt. Anybody else seen anything like this?

 

First I've heard of something like this from any of the 3 Mazda forums I frequent. Sounds like you may have a faulty throttle body.

 

Exactly. As Cam suggested, it may be the throttle body. These are known to give issues on the 03-05 V6 models. Quick way to see if it is the throttle body, would be to take it off & clean it. Cleaning them usually fixes most issues with them. If the problem persists, take the car to your closest Mazda dealer.

-Sheldon.