My Engine is misfiring all the time. During idle it seems to recover and stay at 900 RPMS but as soon as I put it into either drive or reverse the RPMS drop down and it sounds like the enging is going to cut out. When I drive her the enigine is making a putt putt sound, and there is less power. I am going to get the fuel filter replaced and have a look at the distributor cap maybe faulty? I don't know what it could be. The same thing happened a month ago and went away after a day now it has stayed and I have no idea what it could be.This all started after I refuelled the car 2 days ago. Went from Premium unleaded to normal leaded could the fuel mixture do it????

I have been having a similar problem with my 1994 850T (112,000 miles). Sometimes it sputters, pops and then starts running normal. Also it will not take full throttle well. It seems to lose power with too much throttle imput, but when you let off it resumes normal excelleration. After changing the front O2 sensor it seemed to improve the putt putting. My codes showed misfires in each cylinder. I'm beginning to think that the catalytic converter is partially plugged. I will have to have the cat. checked out further. I'll update if anything comes of it.

Check the plugs wrong ones installed

HI Bill
The misfiring and putt putting started before I put in the new plugs. I put in NGK spark plugs they were BCR6ES 11. Could it be the condition of the oil? I got this car recently 2nd hand the last oil changed was in Nov 2001. I just found this out from the previous owner tonight. I have added fresh oil to it while driving it. The last service was it's 165000K in Nov 2001 it has just now reached the 180000K mark. I checked through the record and the disributor cap was change at 90000K should this be replaced as well? Any advice would be great this is my first 850 my previous cars were a 87 740 and an 83 760.
thanks Alex