System to Lean

1998 Dodge Ram 1500 4x4 123,000 miles.
Check engine light came on, truck was running bad. Had new cap and rotar put on, new air filter and changed spark plugs. The plugs were totally black. I cant imagine how they fired.
check engine light is stillon. Had it coded and it blew a 170 or something but it was a system to lean. The truck runs good upon first starting but gettin down the road it hesitates some and just doesnt make the power it used to. Any help would be apprecited