By Ken Tucker
Updated October 18, 2002 at 04:00 AM EDT

On CSI: Crime Scene Investigation — the Coke Classic to ”CSI: Miami”’s instant-hit Diet Coke With Lemon — William Petersen’s Gil Grissom is one cool cat in the broiling Las Vegas sun. But off camera, Petersen is pretty steamed about this season’s ”CSI” spin-off. He recently told the Chicago Sun-Times: ”If our show starts to suffer, I’ll go berserk.” He also doesn’t seem to like his network’s new missing-persons drama ”Without a Trace.” ”It’s another ‘CSI’ show,” Petersen told the newspaper, implying that the Anthony LaPaglia vehicle tools along on the same follow-the-evidence fuel. ”I mean, what are we, McDonald’s?”

Only in the sense of serving millions of hungry consumers, Billy. Over the summer, Petersen’s ”CSI,” even in reruns, frequently topped the Nielsen ratings, a testament to how much fun it is to watch Grissom and his crew solve each installment’s self-contained puzzle all over again. The new season of ”CSI” got off to a bang-up start that included a fine, squirm-inducing example of the show’s patented visual trademark, a computer-generated tour of one part of a corpse — in this case, the trajectory of a bullet entering a victim’s cheek and exiting his temple. (The viewer’s simultaneous reaction to such a bravura stunt: ”Yuck!” and ”Yay!”)

The next week, it was exciting to watch Jakob Dylan and his Wallflowers sell out by singing a track off their upcoming album while portraying a band performing in a Vegas casino. Even better was the plot, in which a famous young actor (Chad Michael Murray), cunningly made to look like a cross between Brad Pitt and ”7th Heaven”’s Barry Watson, was accused of murder. Grissom’s gang had utter contempt for the arrogant suspect — they referred to him as ”movie boy” — and there was a nifty subplot that pitted Grissom against his former mentor, a Dr. Philip Gerard (Raymond J. Barry), who shares the same name as the cop who hunted Richard Kimble in ”The Fugitive.” (Coincidence? I think not: After all, when ”CSI” premiered in 2000, it was overshadowed by the much-hyped but ultimately canceled Tim Daly-starring ”Fugitive.” Ain’t payback sweet?)

But if the peevish Petersen wants to keep ”CSI” distinct from its Florida spin-off, he’d better start badgering his own writers to tone down what could prove a distracting recurring subplot. ”CSI” has always prided itself on refraining from ”personal” story lines — we know little about the main characters other than a few traits that might occasionally affect their work lives (Gary Dourdan’s Warrick is a recovering gambling addict; Marg Helgenberger’s Catherine used to be a Vegas stripper). But late last season, it was revealed that Grissom had a hearing-loss problem, possibly inherited from his mother.

That malady intruded upon the climax of the Oct. 3 episode, in which Grissom took the witness stand at an evidentiary hearing and couldn’t make out the questions being asked. It’s obvious the producers want to add a flaw — a bit of poignance — to the character’s chilly professionalism, but it’s actually a distracting drag on the show’s usual nonstop momentum. We watch ”CSI,” no matter where it’s located, to see tight-lipped pros use high-tech methods to give postmortem dignity to the corpses left behind. Add too much melodrama to that mix, and they’ll just end up with ”Dragnet Goes Six Feet Under.”