Hey guys im new here not sure if this is in the correct place. I got a 2003 rx8 only 50000 miles. Love my car. No problems since iv had it except for cold starts. When the engine is cold it now and again takes 3 or 4 seconds to start. You turn the key and it sounds like its struggling and its rough but it always starts everytime. When the engine is warm it starts straight away. Ťhats the only problem iv ever had. But now its also idling high. Again same thing only when its cold it will idle up to 2000 revs. If i drive it straight away it slightly judders. But Once the engine warms up only takes a few minutes everything is fine. Idling goes back to normal. Lower are Revs smooth. Its only started doing the idling thing since i fitted an induction kit. Not a mickey mouse one either proper expensive kit stainless steel pipes yhe works and it Sounded amazing but i had alot of idling problems and it was really rough in lower revs. So iv taken it off and put the original back on. But now this high idling problem is here. Iv reset the ecu and cleaned the maf. But its still doing it. I know its nothing serious but it is very ennoying. any suggestions what it could be would be great. Thanks in advance

 

Not sure why you didn't notice it to start with but ............. an rx8 will always idle at a higher rpm till it warms up . The colder it is the higher the idle will be .
Suggest you get your battery and Starter motor speed checked to fix cold start.