hello,
ive got the same problem, the engine starts and sounds like a deisel and then it would go quiet after about 5 mins. The problem ive got now is that it sounds like a deisel all day, ive changed oil (shell helix plus), oil filter, even changed the timing belt, transmission oil and ive also added lucas oil to the engine oil.
there has been no change
100 000 mileage done on engine. (but after oil change the engine did quite down for a week and now has returned to the diesel sound.)
another problem that just started was the engine somtimes is seeking ive been told i need another distributor cap (i have iridium spark plugs) and when im driving, after i take the foot off the pedal the rev counter falls below the 750 idle point and then rises back up to the 750 idle.
thanks for all the help