hey guys, just joined to this site to get some ideas. I have 1990 R31 auto sedan that im having some major issues with. It was missing coughing and spluttering. Took it to shop they replaced the air flow metre, the fuel pressure regulator and adjusted the timing, now it doesnt miss but still the odd back fire when you put your foot into it. Its also really really sluggish, like no power at all from a standing start. It does have a leaking manifold/exhaust gasket but surely that cant be whats making it lose so much power. Any ideas guys? Thanks!.