jaywrxsti

hi on the odd occasion (5-6 times in last 3mths) my wrx has been had to start . i have had to put my foot to the floor and keep the starter spinning . when i does fire it idles lumpy . when i the pull away the revs go upto 3000rpm and it behaves as if the throttle has stuck open . after about 3/4mile it idles normally. the fans are running and the cel flashes on and off which i know is the coolant temp sensor but would that make the idle misbehave . i will be changing the plugs at the weekend to help starts. does anyone know what coolant sensor i need as seen few types on ebay (98 wrx wagon) cheers j