Vehicle Runs in Second Gear

What is your question?

My son's 2006 Acura MDX has been in shop for 5 weeks. Mechanic admits he can't fix it. Front cat converter replaced, and cam sensor replaced twice. Plugs replaced. Says vehicle runs, but is in "limbo," second gear. Thought it might be a timing issue. Any ideas? Don't want to keep wasting money with this mechanic.