mine is doing this too.
2000 sport 4.0 ohv engine .
shakes a bit for 30 seconds or so during warmup then smooths out .
what could be causing this?
i have replaced nearly everything...lol
new head gaskets
new intake gaskets
new upper plenum gaskets
new radiator
new hoses
new plugs
newer wires
could it be timing chain related???
motor has 135,000
it was leaking antifreeze from everywhere,thats why we had all the gaskets done .
now i have a small leak at the timing cover yet.
other than this shaky startup it runs great.
ideas???