my 2003 town and country van after i start it and drive it chugs going up hill and blows black smoke some times on a steep hill when it happens it wont go faster then 45 mi an hr

pull an 02 sensor and try it with it out one time. look for a differnce

Fuel pressure regulator over pressurizing. Or a temp sensor manfunction.these vans also have hidden wiring under plenum ( intake) that it touch sensitive that can cause runability issues or damage ecm. Scan ecm first buy parts once. Autozone, pepboys, or o reillys scans for free.