One day the truck was fine, the next day engine light came on and engine light illuminated. Engine light shows 2 blinks pause 6 blinks (error code
26) which indicates air/fuel mixture problem. I checked the air filter, vacuum lines engine ground strap and added BG44K fuel injector cleaner. I do not know how to check the O2 sensor or the ECM. Engine has 98K miles. I cleared the error by removing EFI fuse. Light came back after a few miles. Engine still rough at idle and acceleration. Exhaust smells rich.