Engine ticks, sometimes.
 

Thanks in advance for your help.
Sat. I bought my first Chevrolet ( Silverado 1500 Z71) and the test drive and the first day it drove like a dream but on Sunday I went to get my camper and on the way the motor started ticking and oil pressure drop from 43 to 38. I pull it into walmart and check oil level, its fine. I start her up and ticking goes away. I go get the camper and on the way back it starts again. I pull into Oreilys with a ticking motor and they give me cd2 oil detergent. After siting 5 min its not ticking anymore. I had to stop 3 times in 30 miles on the way home. When its doing this theres smoke coming out the dipstick tube. the water temp is still 210 but the oil seems a lot hotter than usual. This morning I replaced the microguard filter with a wix tall. The truck ran good all day until I hooked my empty stock trailer to drag it home and it starts the whole thing over again. Any ideas?