About 6 years ago my CAT 3126 started to lose power intermittently. I changed the fuel filter, but that didn't help. I took it to a CAT dealer and it was diagnosed as dirty oil. I guess the oil pressu...
I took the motorhome to Carter Machinery in Salem, SC. The tech attached a computer reader and had the codes in a few seconds. I needed a sensor and a solenoid. Parts and labor $600.00 out the door. There was no wait, no hassle and no problems. The engine runs like new.