I have a 95 gmc serria with a 5.7 V8 and when I give it a lil gas it blows out black smoke I just recently changed the oil I went from normal oil to full synthetic I dont know if that would make a differance or not
Black smoke means shes runnig rich. The black smoke is just carbon build up breaking loose. Here's a tip, buy some seafoam. With the engine running slowly pour in half of the can without stalling the engine, then just dump the rest in which will cause the engine to stall, leave it sit overnight and run the next day. This will clean the top end of the engine, and probably get rid of your smoke.