When driving my 2005 Ford f150 supercab-I get a vibration sound between 25mph to 35mph. It last about 2-5 seconds. It seems to be coming from underneath the truck-somewhere between the gas pedal and drivers seat. Sometimes it vibrates and you hear a slight rattle coming from inside the dash- behind the radio. If you give it more gas it goes right away. If you accelerate from a dead stop at a good pace it doesn't happen--only when you accelerate slowly. Any suggestions?

 

I had a similar noise and it turned out to be the air intake snorkel that goes into the fender. It came out and vibrated against the metal. Popped it back in place and the noise went away. If you have the stock intake, might want check it out.