Okay so my rx8 has 100k miles on it and lately it takes a little while to start (sometimes longer then others) and after it starts itll rev up(and im not pushing the gas or anything). Ive read some stuff and I wasn't sure if this was compression problems or if it was coils or the starter or anything(I don't know the last timethey have been replaced or checked). And I was also wondering if rebuilding the engine would fix compression problems. Thanks.

 

That's the exact point of a rebuild - to fix compression issues. Which, really, is the point of any rebuild even on more conventional engines. Have you had the engine compression tested? Are you having Hot Start issues yet?

 

Yeah I have to like crank it over for a little while before it starts but i havent had the compresson tested yet

 

All the time or only when the car is warm?

 

Its mainly when its cold

 

Could be a vacuum leak, or dirty ESS.

 

Is it a 6 speed?
When you say it revs up do you mean the rpm's are jumping up and down?
You may want to check and/or replace the neutral idle sensor.
If the rpm's are jumping up and down then push in the clutch, if the idle returns to normal then it's most likely the switch.

 

I took it to a mechanic like a month ago to have it checked and he tested everything and said that he thought it was the throttle body

 

which you guys can tell it did not work haha when i did research i thought maybe it was compression problems but im not sure now

 

You're going to have to be more specific about what it's doing. Also, if you don't know when your coils and spark plugs were last changed, it's time to change or test them.

 

Is it hard to change the coils? And how much do they cost.

 

The coils are not hard to change there is a DIY here in the forums some where. Just look. As for prices, hit up a Mazda dealer or Auto zone or Pep Boys. I would suggest only buying OEM coils.

 

If you're ready to shell out dealer prices, you may as well get BHR (BlackHaloRacing) coils, so you never have to change them again.

Otherwise AutoZone coils are fine and cheaper, just be aware that every 30,000mi or so they need to be changed.

 

I agree, BHR coil upgrade will be much more reliable and pay for itself easily. Amazing warranty as well. Most of us here in the forums are running that kit

 

Personally, I would buy OEM coils to start before investing in an upgrade. At least until you get everything squared away and are confident you have a good 8.
That's what I did.
You can get Lifetime warranty coils from Advance Auto, and online coupons can save a bunch of $$.

 

Are these the right things? https://www.am-autoparts.com/Mazda/R...EDoaAiFG8P8HAQ

 

If it's all 4 at that price, I wouldn't trust them. There are counterfeit parts on the internet.


A normal aftermarket price is about $35 each.
Stick with well known sources that stand behind their products.