I bought my '04 M/T last october, with 59k miles on it (now has 63k). Ran great for about 5 months until one day while idling at a red light about 2 months ago it just died. Started it back and kept driving, but it wasn't as smooth as before.
Ever since that day the car has never been the same. It used to start at the flick of the key, now it takes like 3 secs of holding the key and it starts after 3 or 4 starter turns.
Used to idle at 1000rpm, now it idles at 750rpm and it's really shaky, feels like it will stall and any time.
I used to put in 1st gear and start releasing the clutch at like 1200-1500rpm with no problem at all. Now if I start letting go of the clutch at below 2000rpm on 1st or 2nd gear the car will have half the power and it will jerk.

Other than that the car has no weird noises or anything else, tried pulling the codes but not a single one came up.

Changed spark plugs and wires less than 2000 miles ago. Oil and filter change 1500 miles ago. Seafomed a week ago.

My mechanic said that it feels as if the car's timing was behind, but there is no timing belt!

Bought the car at a used car dealership, I have no way of knowing if the previous owner did all the recalls, or if any dealership will do them, since I'm not the original owner. This is the newest car I've ever had so I am not familiar with the way dealerships work in this cases.

Please help!

ignition coils

Coil packs.
Your spark plugs are probably not getting the charge they need from failing coil packs, so you have weak ignition, weak starting, unstable idle, etc...

Assuming the original coil packs were changed at 30,000 miles you are due for a 2nd change. It is possible you are on your originals as well, we have seen it a fair number of times. They can last quite a long time before starting to fail, or they can fail quickly. Someone on here replaces them every 7k miles or so. My originals just started failing at 39k.

Don't get screwed on the coil pack price, it varies from place to place. Cheapest is around $32 each, highest I have seen is $80 each. They are a snap to change, the other end of the spark plug wires from the spark plugs.

Wouldn't I get a misfire code then?
Without a timing belt, how do the spark plugs know when to fire?

I got quoted $260.- for the 4 ignition coils

^payin wayyyy to much, well yeah depending on how bad they are....

heres a cheaper place http://www.buymazdaparts.com/results.cfm?modelcode=rx8&catid=3

should take like 15 minutes to replace

Wouldn't I get a misfire code then?
Without a timing belt, how do the spark plugs know when to fire?

Yes/No. Historically, failing coils only generate misfires codes once they are REALLY bad. Not every misfire generates a code.

The 'timing' is based on e-shaft sensor I believe, no belt.

DIY:
http://www.rx8club.com/showthread.php?t=168162&highlight=DIY+Coil

I changed all 4 coils ($35.- each) and it worked like a charm!!!
I can't thank you enough!