When i put my key in the ignition and turn the key the needle on my rev counter jumps upto 800rpm and sits there untill i start the car...

Have noticed it a lot more during the cold spell weve been having, and i dont recall it doing it when i first bought the car (4 months ago).

Any ideas???

 

i have a 1994 subaru impreza turbo and my revs started to go funny after i go past a certain mph and rev i looked under the bonnet and found that some idiot had cut my lambda sensor and the plug off the actual car, i have recently got a new sensor but need help wiriing it on the sensor the wire colours are as follows
2 white 1 grey and 1 black
however on the car they are
1 orange 1 red 1 black and 1 grey

need help asap thanks

 

I doubt his problem is due to a lambda sensor as thats to do with fueling. His sounds more like an electrical problem.