I have a 1990 7.3 idi that at start up shakes,misses, spits, smokes exsessively. After it warms up it smooths out but still smokes more than usual. Have changed fuel filter, air filter, fresh fuel with marvel mystery oil. Have no fuel in coolant or oil. Does this in cold weather as well as warm, even when heater has been plugged in. She runs good down the road but smokes more than usual.Has a grey to white color smoke and smells real rich. Any suggestions would be helpful.

 

It kind of sounds like time to pull the injectors and have them tested. Most likely you have some bad ones

 

Yep.

 

just replaced all 8 20,000 miles ago. Any other ideas!

 

Just because they are fairly new doesn't mean they couldn't have gone bad. Loosen the lines one at a time and see if the engine doesn't change when it is loose. Then pull the one that makes the least amount of difference in the way it runs and have it tested. It is also possible that you have a compression problem.

 

I will agree on the compression issue. Does the smoke puff AKA only one cylinder is doing this? Also, pull the oil fill cap. Are you getting a puff out of it or feel like there is alot of air, smoke, steam, ect blowing out of it?