Nissan Pulsar Forums

I bought my Pulsar 1.2 petrol second hand on a 64 plate. Soon after purchase i noticed three or four metallic clicking sounds coming from the engine when accelerating in 4th and 5th gears accompanied by a large puff of light brown smoke coming out of the exhaust. It is the ONLY fault on the car and is spoiling my ownership experience. Anybody got any idea what is causing this problem?. It's already been in to a Nissan main dealer who said it displayed a fault code that they cleared on their diagnostics machine. It hasn't fixed the fault so it's going back to the garage again.