Engine Mechanical
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2003 Pontiac Grand Prix, 2003 Pontiac Bonneville, 2003 Chevrolet Monte Carlo, 2003 Chevrolet Impala, and 2003 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
A variety of engine mechanical conditions may result in a hard start condition without setting a DTC. To determine if any of these conditions exist. See COMPRESSION under MECHANICAL INSPECTION under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article.
If incorrect compression is detected, check for carbon build-up, cam timing, oil fouling, incorrect parts, bent pushrods, rocker arms, valve springs, cam lobes, intake/exhaust manifold flashing and faulty head gaskets.