Here’s an action movie that could’ve used some tips from the Philistines. Like, “Instead of a scholar, let’s make Tom Hanks a blind sumo wrestler with 24 hours to live.” And “Instead of a cryptographer, Audrey Tautou oughta be a whore. I got it, an extraterrestrial whore.” And all that history crap? “Lose it.” Action and ideas — they get in each other’s way, pal. And director Ron Howard didn’t want to choose between ’em. Good impulse, not such a good result.

It’s easy to imagine that while The Da Vinci Code novelist Dan Brown was hanging around the set, he gathered new doubts about the filmworthiness of his best-selling tome. His scheming bishops and tortured fanatics are even more cartoonish in the movie than they were on the page, which is as the good lord intended. In aiming The Da Vinci Code at the cineplex, though, neither Brown nor Howard has figured out what to do with all the primers on Templars, symbology and Mary Magdalene that made this story about suppressed womanhood and a modern quest for the Holy Grail so controversial and popular in the first place. In the novel, Brown just heaved them into the mouths of his characters like 36-ounce porterhouses, counting on the reader to chew along. But amid the flick’s hyperdrive, the lectures are buzz killers.

Not that they aren’t well-handled individually. Howard and cinematographer Salvatore Totino have turned the book’s encyclopedia asides into nice visual abstracts of blood and conflict, with arty dissolves, grainy textures and Renaissance pigmentations; Hanks’ solo spiel about the Emperor Constantine is a classy bit of fireside storytelling. The problem is the pace, which suffers when demands of explication force Howard to pull his foot off the gas.

When classic action vehicles take a break from the frenzy, it serves not as an opportunity for a symposium (we cut class to go to the movies) but as a chance for the genders to exchange bodily fluids. Brown’s clearly saving that for a sequel, however, so sex is barely a shrub in the convoluted Da Vinci scenery that speeds by in chases across France and England. And besides, the puffy Hanks and the virginal Tautou produce about as much consommé potential as a turnip and an artichoke. As plot mules, they’re serviceable but fibrous.