Snowshuffle523

Not seeing anything out of the ordinary but I need to pull it again soon. I’ll try to get some live data when towing over my 4 hour trip. I figure it can’t be too high or I’d expect it to throw a code, but who knows I ended up taking it to my mechanic last week and they said they couldn’t find any silver bullet but the intake had some heavy oil buildup (I don’t have a catch can) and carbon, they did a clean on it so I need to do some more towing and see if that helps. I can’t imagine it will make a massive difference. I don’t expect a miracle for MPG but I’d love to get 8-9mpg when towing vs 5. If you have any other things to check I’m all ears! I appreciate your response!

I can’t seem to figure this one out. I’m getting around 5mpg when towing a 7x14 enclosed trailer with a UTV in it, roughly 5k pounds total. I used to be able to get around 8-10 towing at 70mph but it’s taken a steep drop off lately. My friend 2018 Silverado gets 8-12 when towing my trailer. Tire psi at 38 on the truck and 50 on the trailer (max rating for the tires). Engine has 88k miles, air filter is clean, MAF sensor in clean, plugs and wires were replaced about 3k miles ago. Combined my is roughly 15-16 when I’m not towing, all driving is done on mostly flat roads with only slight inclines. Truck is bone stock with no lift, running LT tires, does have a bed cap. The data below was towing with no significant head or tail wind. I did some digging with an OBD2, no active codes, short term fuel trims are around -1 to -5 and long term at -7 when cruising at 70mp with the trailer. Fuel pressure sits between 40-56 psi, engine load at 70mph sits between 80-100%. the only thing I’m not sure of is the injector balance test, one side of the engine sits at 37 psi drop and the other side is 46 psi drop. Is that expected to have one side of the engines with such a spike in psi drop? I did some searching and couldn’t find an answer, I thought psi drop should be roughly +/-10% across both banks on injectors. Picture for reference