I have a 97 and recently put a #100 plate in. I've been noticing that it blows grayish smoke. I've checked the fluids and no signs of mixing oil and water. The motor has 250,xxx miles on it and it runs good, seems to miss a bit when cold but other then that it runs strong. It still has the original injectors, and to my knowledge the timing has never been touched. I'm leaning towards wore injectors. I noticed when it got ran on the dyno for emissions last month that when it was in a hard pull the smoke would kind of build up and puff a few times. Kinda of like it was getting extra fuel now and then. It also smokes a little blue when you first start driving if it's still cold. What do you guys think? I'm I on the right path with injectors or is there something else I should be looking at? Oh and when it has the stock plate in it dosent smoke gray or really any color for that matter.

 

timing may have slipped through the years....

 

Get injectors popped and check the timing. Mine would pour out gray smoke till I put new injectors in, but timing should be checked too.

 

Mine has recently started the same thing. I had one injector a few thousand ago completely go bad on me and being a college kid i could turn loose of that much money for new sticks and im starting to get alot of grey in my smoke after i get on it and if it idles for awhile and you just run it up to 1500-2000 your gonna get alot of pure white. Just started this very recently. Does your truck pop or spudder when cold? That will be a timing thing most likely. It can be other things but retarded timing is usually the answer.