wcrocco

Hey guys, new to the site. My issue may sound like other threads but I can't find any with the same issues. Anyways any help would be appreciated,
Away from home and my 85 runner picked up a rust free 87 runner here in northern Alberta thing has 380xxxkms.
Previous owner said he hydro locked it, no water in oil. Air box or anywheres, starter was seized so replaced engine fires right up idles like a rolex, seems to have very poor throttle response engine will rev up to 3000rpm and backfire out the exhaust and die back to an idle. After it warms up it starts to rev up and down. It's throwing a code 12 for the K/S.
did a dry compression test numbers are good 155-170psi across the board, tension on the timing chain is good guides are a1. Timing marks with the balancer set on 0 degrees almost looks like the cam might possibly have jumped a tooth? I know these are a interference type motor so hoping the valves haven't met the pistons yet.
Fuel pressure is good. Has stale fuel tho going out to drain it and replace the filter now.