2.5L runs rough in third gear. Black smoke

[GoodGrief88]

My 1993 with the 2.5L has been sitting for about two years when we bought it. Changed the oil, fuel and air filter, treated what gas was in the tank and added ten gallons of 93 octane. At first it ran rough and smoked all the time but now after putting maybe five miles on it it's pretty much only running rough once the transmission goes into third gear. That's when I get the black smoke too. Any advice would be greatly appreciated as I really don't want to just throw parts and money at it. Thanks

[EuroTec]

Could be sticky/leaky injectors, running a bit rich. Add some Seafoam gas treatment to the tank and drive it some kore. It just might clear up.
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