One problem related to steering idler arm has been reported for the 2003 Chevrolet Express. The most recently reported issues are listed below.
Front wheels off the ground, steering wheel centered, held firmly in place, there is no play, looseness in steering system. Wheels turned 10-15', either direction there is approxmately 1" of play between wheels and steering wheel. Condition is the same by moveing either front wheels. Both wheels react to each other but not to the steering wheel. There seems to be a design defeciently in steering linkage or turbo-boost pump. Another 2003 2500chev van, 28000 miles has the same problem, mine has 13,338 miles 2003.