NY- David Lee Roth vowed on the air yesterday morning he will not quit his morning gig on WFNY (92.3 FM), but did little to derail growing rumors that parent CBS Radio has decided he isn't working out as the replacement for Howard Stern.

Roth said he had received "four letters in the last five days" from CBS brass ordering him to make "extensive changes" in his on-air style.

He is complying, he said, "because it's been made clear that the alternative is termination or disciplinary action. ... So I'm going to give it a try. I've invested too much in this show not to."

The changes included the elimination of background music and three of his sidekicks, Animal, Sasha and B. Young. Instead, he said, he has been told to read the news and comment on it.

"It's a traditional format that works very well for someone who has done it for 20 years," he said. "But for me, who's doing my own thing, it's like they want to me to do someone else's show."

The rant came just days after Roth was off the air. He said yesterday he had been taken off the air for a few days, while a CBS spokeswoman said earlier this week he was off simply because he was in transit to New York from Miami.

And for the second time in a month, he accused CBS Radio CEO Joel Hollander, general manager Tom Chiusano and program director Mark Chernoff of not letting him do "the show I was hired to do."

Although CBS has publicly said it is not surprised by the numbers so far, which show Roth's audience less than a quarter what Stern used to draw, there are indications the company wants to at least make some adjustments.

Roth yesterday admitted that he "really floundered around" for the first four to six weeks. "I didn't know what I was doing. I asked for rehearsal and they didn't give it to me.

He's staying with it "for now," he said, "because I've invested almost a year and literally hundreds of thousands of dollars of my own money in this - for the music and so on. Those pictures on the side of the buses? I paid for them.

"Now, if I don't play, I don't get paid."