Please help. Code P0141

po141

I have a 1996 bravada with 89000miles. my prob is whene i start it when it is cold and drive it it is taping it does not do it at idel. it starts about 2300rpm and up i am also getting a PO141 i use mobile1 5w30 and a purolater PureONE filter. has always had mobile 1 i changed it every 3000 miles also when it shifts and the rpm drop it stops and starts as the rpms go back above 2300. only hear it in the car does it in or out of gear