I have a 2004 GT model.
I just got the car recently and realized gas was terrible.
I was getting around 11mpg... I switched out the oil filter and now I am getting around 13-14MPG. The car has no other mods at all...
any suggestions or ideas why this could be?

Also, my drivers side speakers will randomly cut out for a few seconds about every 2-3 mins. I have not had a chance to take a look at it yet, but does anyone know if this is a common problem with the stock Bose system?

 

First question: Have you checked your compression? Although 14mpg isn't unheard of, many people get combined mileage closer to 18-20 with a car adjusted properly and reasonable driving habits. It could also be time for new coils, wires, and plugs. If the previous owners didn't change them, then you are over-due.

Second question: Not a common problem. Only the driver's side? Might be a loose connector.

 

I just sent a message to the previous owner and he said he did not ever change the coils plugs or wires and he's put around 40k miles on the car. Guess its time to check that. Could that really cause that much diff from 18mpg down to 13-14 mpg... Also, I just read on another thread that the aftermarket intakes are supposed to be not so great for the rx8's. I put a K&N aftermarket air filter and customized the box for it to fit in place of the stock paper air filter. Is there anything I should be worried about in doing that?

 

Check on your spark plugs, wires, and coils. How many miles does the car have?

 

another question... is there any way to check coils at all?? or just change them to be safe!

 

car has 70k miles but the engine was replaced in 2006 when the car had 40k on it

 

If you have 30k on the new engine, it's time for new coils and plugs.

I only use Mazdaspeed accessories so I can't comment on the K&N.

 

If I were you I'd also replace the plug cables while I was at it.

 

any idea where I can get these for the best price? i remember seeing someone posting about a good site online to get coils but I can't find the post anymore. Thanks for the responses. I am new with the 8 and still learning

 

For supplies check on the vendors of the forum. Race Roots might be a place to start: https://www.rx8club.com/moved-thread-holding-area-119/regular-maitenance-needs-one-place-182550/
Search on the forum as well and see what others recommend. There is lots of discussion about wires, plugs, and coils. You can also find how to change them yourself. All you need is to take out the front left tire.

 

I was just checking around and found this thread. Perhaps you might be interested:
https://www.rx8club.com/showthread.p...hlight=battery