Y&R Michael Muhney -- I'm SO Much Better Looking Than Zach Braff

Michael Muhney -- who was fired recently from "The Young and the Restless" for allegedly groping his co-star's boobs -- was also fired from "Veronica Mars" -- partly because his ego was out of control ... sources connected with the production tell TMZ.

A source connected with the production tells TMZ ... Michael told multiple people on the show he was up for the lead in the TV show "Scrubs" along with Zach Braff, but he was just too good looking.

One source said, "I'm not a fan of Michael's," adding, "He had a VERY strong sense of self." We're told the consensus was ... his personality was just really tough to take.

Another source tells TMZ ... the final straw was that Michael allegedly released portions of the season finale online. He was fired, and the way they killed him off was great. He was investigating a crime inside a house and got shot. His last words were, "I smell bread" ... and then he died.

But we spoke with an actress -- Jenna Zablocki -- who was Michael's on-screen love interest in "The Portal." She says, "He was a gentleman, professional, and a really cool guy."

As for the Y&R firing ... the allegations were hardly a secret ... last month a user on a popular soap blog had posted details of the alleged breast-grabbing allegations.

We called Michael's rep but did not hear back.