Here is my situation. Kept getting a CEL (04 rx8), so i took it to the dealer and they replaced the Cat and 2 of the ignition coils(Dec 2009, 48,000 miles). Dealer told me to rev it high on the way back to clean the carbon out (50 mile highway trip/little traffic/cops). Noticed when i got back into town that the car had a slight power dip. Drove next day no problems. Around town i have no problems but have taken it on a few road trips and once i come into town (after driving 75-85 mph) i notice the car is very sluggish. Had plugs replaced (Mar 2010, 51000 miles) and the recall issue the other dealer didnt do which still has not fixed the problem. Dealer said its a valve near the manifold which costs about 230 plus labor bringing the bill to 750 or so. Today the car just died on me at a light and wouldnt start for a couple of minutes. CEL was on when i tried to start it. the car finally started but is sluggish. CEL is off. Also, there is some type of rattle noise when i am having the power problems which i think is coming from under the car. My question is does this sound like and engine failure problem and the dealer is trying to squeez money out of me before saying yea it really is the engine or could it really be this valve he was talking about?

 

Find out what CEL it is, could be a stuck SSV valve perhaps?