I'm going to assume this is the 2.4L engine since you ssid it has a timing chain.
And since this truck only has 140K miles I'm going to rule out piston slap. These trucks last WAY longer than that. It is possible to have piston slap at 140K though, I've seen it on my 1991 GA16DE Sentra.
Did the noise go away after the additive? You can try using a heavier grade oil. On older engines I tend to use 10W40 when the weather starts to warm up and 10W30 for the winter. I find the heavier oil prevents leaks and keeps the car running better. For example, my Subaru EJ22 with 160K miles makes no noises with 10W40, but has a little tick from the roller rockers with 10W30.
Another possibility is noisy injectors. try adding some Gumout Regane fuel injector cleaner. Normally I buy the cheap stuff from Gumout because it works just fine, but when I went in to AutoZone a couple days ago the Regane was on sale. If it is take that, if not just stick to the concentrate stuff. Noisy or tired injectors can make a tick that matches the intensity and frequency of a valve tick, so it's a good idea to check them while you're searching for answers. Take a big screw driver and put it to the injectors when the engine is running, with your ear to the plastic handle to better hear if an injector is making the noise.
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