Idle
 

Hi once again guys,,, Another little gremlin has just occurred, B200F,,,went out did 40 miles no problem,, came back 6 hours later after 20 ish miles i noticed that it was idling at 1,500/2000.rpm,,so while at traffic lights turned off and restarted and it was idling ok,, So what is happening i wonder,, although this has happened before,, Anyone else have this happen,, and does anyone know why.?? regards Adrian..

First culprit is a dirty Idle Air Valve - the shiny alloy can underneath the inlet manifold. It needs removing and cleaning with carb cleaner quite regularly otherwise it starts to gum up with fine soot, causing the sliding valve to stick.
You can often sometimes nudge it by blipping the throttle.

Next is the Throttle Body, the small brass nipple on top of the inlet manifold, and the flame trap pipework.

Check for leaks in the convoluted air intake hose, loose hose clips, air filter.

I will do that ...Thank you clifford,,!!!!