Ok, I bought a used 2004 RX-8 (automatic) over a year ago. It drove fine but now the car shakes and the idle is rough when stopped at a stop light and I am in gear. When I hit the gas and rev the RPM's to about 1000 the idle smooths out.

Also, I feel as though I lost some power and my gas consumption isn't that great (not that I was expecting to get hybrid type gas mileage).

I had the spark plugs changed a few months ago, cleaned the injectors, drained and replaced the transmission fluid and have have more than a few oil changes.

Any ideas what could be the problem?

 

sounds like classic leads and coils .............

also : clean the maf