I noticed that acceleration is a little slower. Seems like there is a slight hesitation. It’s seems to misfire around 45-50 mph going up hill. Today I was towing a load of wood had some in the back of the truck. I stopped at a stop sign. Went to go up the hill. It seem to cut out a bit. Service engine light flashed a few times and went away once I was at the top of the hill. Tonight driving 45-50 mph up a slight incline it shook again. I changed the fuel filter the other after being told that might be it. Any suggestions on where to start? No error code. Should I change the plugs? I bought it with 150K miles. It now has nearly 190k. I don’t know when the plugs were changed last.