I am new here. I have a 2003 ford ranger 4.0l SOHV 4x4 with 183k miles. I’m have a problem with it misfiring only at idle. Only does it in park. I have a scanner that shows the number of misfires and as soon as you put it in drive it stops missing. There are no codes besides for a random misfire code sometimes pops up.

Truck has new-
plugs
wires
ignition coil
intake manifold gaskets
injectors
throttle body gasket
Valve cover gaskets
map sensor
crank position
cam position
tps sensor
fuel pump
fuel filter
vacuum lines


At this point I am lost. I took it to a shop and they did a compression test and every cylinder was good. They said they couldn’t find anything. They thought the valves could be gummed up but I remember when I had the intake manifold off the valves looked fine to me. One thing I did notice is the driver side timing chain was loose. The rear on was tight. At the time I wasn’t aware of the known time chain guid problem so I didn’t really look. I’m thinking it could have jumped time? But the is not timing chain tick or rattle. Please lmk what you guys think. I really appreciate it.

 

4.0l SOHC, just to be clear.
The stories I've read here don't mention the chain jumping, though it seems reasonable to assume it has/would.
Put it in R to see if it stops missing then too. I don't know how loading the engine that wee bit would affect a slackened chain.
I think the front (driver's side) hardware is accessible with the engine in the truck.