When I switch my Toyota Avensis would make a noise but when in gear stops?

When I switch on my Toyota Avensis Verso (2003 reg) would make a noise but when I put it in gear in gear stops.

The AA man could only get it started with a spray cleaner sprayed into the air filter.

Previously (for the past few months) it has lost power on&off when driving it e.g. on climbing hills etc

Last year I had the SCV replaced and EGR cleaned.

What do you suggest I do?