When Cameron Diaz, masquerading as a perky Swedish cupcake, prances into a Mongolian bar and mounts a mechanical bull with ridiculous, toothy glee, it looks like "Charlie's Angels: Full Throttle" is ready to deliver the same giddy, glorious goofiness as the first movie.

Well, yes. But also no.

After endless rumors about on-set feuds, budget overruns and the lack of a finished script, the original big-screen "Angels" three years ago turned out to be a delirious surprise. Sure, sometimes the movie just seemed to be throwing comic ideas at the wall. But most of them stuck, hilariously.

"Full Throttle" is much more miss than hit. Natalie (Diaz), Dylan (Drew Barrymore) and Alex (Lucy Liu) return as Charles Townsend's giggle-and-jiggle Angels, who spend as much time donning skintight costumes and multicolor wigs as they do fighting baddies.

This time, the wisp of a plot used to justify their fashion statements has to do with the search for two stolen top-secret encrypted rings. Brought together, the rings reveal the names and addresses of every person enrolled in the Witness Protection Program.

In other words, this is some jewelry every organized crime family would be happy to pay big money for.

So far so good. But within the opening minutes, "Throttle" succumbs to the disease that's weakening a lot of current movies. Diagnosis? An advanced case of CGI-tis.

The flick relies heavily on computer-generated special effects that may be intended to look har-har cheesy, but just look cheap. There's too much cribbing from the "Matrix" flicks' midair slo-mo "bullet time" effects.

They were a fun ripoff in the first "Angels," but here they just seem lazy and secondhand. The fight scenes, in particular, defy all those pesky physical laws, like momentum, gravity, etc. It's funny at first, then tiresome.

The plot sometimes grows muddy, and good actors get shortchanged. Example: When the Angels land at a dirt bike competition, there's a lot of chasing and crashing, but the action is shot so confusingly, good luck following it.

The movie wastes the great John Cleese, stuck doing reaction shots as Liu's father, who mistakenly thinks she's part of a three-member prostitution team. Bernie Mac gets strong laughs at first as the sequel's new Bosley, but fades into the background.

And rising teen heartthrob Shia LaBeouf ("Holes") is in the movie so little, it's hard to remember who his character is.

OK, so what about the good stuff? Well, the stars are as sweetly charismatic as ever, though Diaz never has a moment as funny as her spank-tastic "Soul Train" dance from the first flick. Nor does Liu get a chance to top her dominatrix-consultant scene though she does show off her skill with a whip.

There's an amusing "CSI" spoof, as the Angels draw amazingly specific conclusions from the flimsiest physical evidence. Movie buffs will dig the nods to "Raiders of the Lost Ark," "Singin' in the Rain," "Grease," "Cape Fear," "Night of the Hunter" and more.

The outtakes at the end are adorable. There's a sweet cameo by original TV Angel Jaclyn Smith and appearances by Bruce Willis, Pink and the Olsen twins (!). And best of all, there's no Tom Green.

As for the return of Demi Moore as evil former Angel Madison Lee, let's just say the advance hype is a lot greater than her follow-through. Whatever Moore paid trainers (or surgeons) to look good enough to hold her own against Diaz in a bikini, it was worth it.

But her sullen, humorless performance proves that one thing she didn't spend any money on during her six-year hiatus was acting lessons. She's a glamorous washout.

I hate to be harsh on a movie that, as those outtakes show, the stars had a great time making. But the sequel rehashes the same old stuff and never hits a new level of fun.

You'll enjoy some isolated hee-hees, but the first "Angels" was nonstop laughing gas. Directing in an even more hyperactive style than he did with the first movie, McG would have been wiser to ease up on "Throttle's" throttle.