I picked up a 240sx this summer that had 'rod knock' that made the clutch feel funny.... or so that was the story I was told. The flywheel bolts had not been torqued down.
The car has an SR in it, the knockoff aftermarket oil pan was leaking from the entire mounting flange due to a whole tube of silicone and the wrong length bolts being used.
Battery relocated to the trunk with household wire (like they robbed a construction site) battery of course was not tied down.
The blow off valve stopped working, it was situated in front of the left wheel, pointing upwards so it filled with water.
About half the bolts on everything the kid touched were missing.
some of the intercooler tubing was installed over other tubing to 'fill in' the gaps in the tubing
ECU, Fuse block and other misc electrical components were not bolted down
Rear glass was never glued in, suprise I found this out while cleaning the glass
I was curious why the headlights looked like they went opposite high-low when switched from high to low.... the passenger side light was installed upside down.
It had no fan, fan clutch, or shroud.
The front cover had been installed after the headgasket causing it to fold the headgasket and making for a massive leak.
P/S pump had been un-installed because the aftermarket line leaked really bad/had the wrong fitting.... the fitting was just installed backwards lol
Im sure there is more, luckly I got a great deal on the car and its proving to be a great car once all the jankies have been sorted.