 Time is money. When the check engine light comes on with reduced power, that could mean that your engine is in D-rate, protecting itself from damage until repaired. If this happens in the Portland area, call Ultimate Truck Service first. They keep diesel trucks and pushers road-ready, experts at solving emission issues. In an emergency, Ultimate Truck Service will come to you within 25 miles or have your tow driver take you to Exit 9 on I-5 Ridgefield. Ultimate Truck Service. They keep you rolling.