My 300D with 240K miles runs
just fine when I rev it or drive on the road, but when it drops rpms down to an idle, the
engine may start jumping, missing, and idling
rough and also blows exhaust smoke heavily.
It runs just fine on the road, but takes
these 'spells' idling very rough. It's not
all the time on idle, just at times. The idle is set where it should be. I've also cleaned the injectors with LM Diesel Purge. Any ideas? thanks!