Democratic Gov. Gray Davis is leading Republican challenger Bill Simon in a new statewide survey that also found most California voters were unhappy with either candidate.

With less than six weeks before the election, Davis leads Simon 40 percent to 32 percent, a slight decline from his 11-point lead in August, according to the poll released Thursday by the Public Policy Institute of California.

Nearly a fifth of likely voters are undecided and many think the race has failed to focus on important issues. Voters also said the millions of dollars in campaign television ads on airwaves statewide have been generally unhelpful.

"They just walk away from both of these candidates at this point and say that they are really lacking in terms of the substance that they are providing to this campaign,'' said survey director Mark Baldassare.

Fifty-five percent of California voters said they are dissatisfied with the choice of candidates for governor and more than half of voters said they are less enthusiastic than usual about voting — sentiments that have political experts worried that turnout this year will be dismally low.

Davis is receiving strong support from Hispanics, women and independent voters and has a wide advantage over Simon in the largely Democratic San Francisco Bay and Los Angeles areas, while Simon is leading by 45 percent to 30 percent in the fast-growing Central Valley.

The poll was based on a survey of 2,019 Californians, including 1,588 registered voters and 1,005 likely voters, conducted from Sept. 12 through Saturday.

The poll has a margin of error of plus or minus 2 percentage points, with a plus or minus 3 percent margin of error for the questions asked only of likely voters.

Less than half — 49 percent — of adults surveyed said they approve of the way Davis is handling his job, while 44 percent say they disapprove and 7 percent said they don't know. Among the smaller group of likely voters, however, Davis' ratings were lower; 52 percent of likely voters said they disapproved of his performance, while only 42 percent approved.