LOS ANGELES — Dave Della Terza enjoys kicking "American Idol" around on his Web site that encourages viewers to vote for the most awful contestant.

But even Della Terza is rooting for television's top-rated show when it returns for its eighth season Tuesday. The two-hour debut airs at 8 p.m. EST on Fox.

"Last year really bored me. The show seemed really desperate. I want it to go back to being the good, cheesy fun it was," said Della Terza.

The singing contest remained TV's No. 1 program last season but saw a dip in viewership, averaging about 28 million weekly viewers vs. the previous year's nearly 31 million weekly average.

That represents a smaller loss than suffered by many other shows in what proved to be a lackluster 2007-08 season, one disrupted by a writers guild strike. It's also impressive stability for a veteran series.

Those behind "American Idol" express confidence that its drawing power remains intact, but they're tweaking the formula to freshen it and keep the downward trend to a minimum.

Executive producer Ken Warwick concedes the ratings probably will "drop a bit" again this season. But a major overhaul was not considered, he told a teleconference.

"There were no panic changes," Warwick said. "It wasn't, 'Oh, my God, we've dropped 7 percent. What are we going to do to change the whole show?' This wouldn't have been on TV for eight years if it wasn't doing it right."

Fox is banking on the show, which last year helped make it TV's most popular broadcast network for the first time with a strong finale in which David Cook bested runner-up David Archuleta.

Walt Disney World in Orlando, Fla., also is betting on the show's continued popularity: The theme park is opening an American Idol Experience attraction next month, allowing visitors to sample the show.

Loyal viewers who tune in this season will easily spot differences in the formula and faces — most notably with a new judge, Grammy-nominated songwriter-producer Kara DioGuardi, joining the original trio of Simon Cowell, Randy Jackson and Paula Abdul.

Cowell, the show's acerbic driving force, takes the role of tiebreaker when the panel locks on whether to keep or dump a contestant. He's both singing DioGuardi's praises but reserving judgment on how her addition will pan out.

"She's written hit songs. She has an opinion, which is very, very important. She talks a lot," Cowell said — and he means as a compliment.

That said, "the panel has a unique chemistry," Cowell added. "I genuinely don't know until I watch the show ... whether this is a good thing or a bad thing."

Della Terza regards DioGuardi with a skeptical eye, and ear.