this has been happening for a long time, but im getting really tired of it. just driving around, the truck runs fine. but if i go out and run hard on the highway, or tow my boat( which is only a 17 footer), when i come to a stop in gear, the oil pressure flatlines, and the engine starts to stumble and die. it only takes a tiny bit of pressure on the go pedal to keep it running, but that is a pain while mauvering a trailer. if i let it idle in neutral for a good 45 seconds to a minute, then go to move it again it will idle fine. this also happens more frequently as the air temperature exceedes 85-90 f.