E30 Zone

My is runs fine however when i am in 5th and about 3500rpm it runs a bit lumpy, it doesnt hapen at any other rpm. Does anyone know why this is and suggest any solutions? Thanks

manifold air leaks ? the rubber hoses under the inlet manifold fall to bits over time . but you may have more luck in tech help forum

Mine idles like a bitch at the moment because i need a new air inlet hose and i think i should carefully check all the vacuum pipes.