I am getting a P0401 code on a 1997 Isuzu Rodeo V6 engine with approximately 140,000 miles. EGR valve has been replace a few years ago. The check engine light comes on and sets the P0401 code when the fuel tank is 1/4 tank full or less. When you fill the tank with gas the check engine light goes out after you drive the vehicle for a while and cycle the engine on and off. The check engine light will come on when the tank again drops below 1/4 full. Any ideas as to the problem.
John Holley