I been debating for 2 years to get and RX8. I bought a 2005 RX8 AT and it had 50K Miles. Ran great for 1 week. 1 day I was driving home and all of sudden the car died at the stop sign. Then it took 5 seconds to start back up. Symptoms the car is experiencing
*rough Idle
*Stall out or Stumbles when I am pressing the gas to accelerate from a green light or stop sign.
*When I open the hood I hear AIR coming from the Engine Bay Area **NEAR TB OR INTAKE MANIFOLD**
*Car takes 5-6 seconds to full crank up
*Car Max Speed was 105-107 on even level Highway.. It will not go any faster
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No CEL so far
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Repairs I have done
*Changed Air Filter
*Changed Coil Packs
*Changed Spark Plug & Wires
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*Some people say its
-A Vaccum Line Disconnected
-Fuel Pump going bad
-pump resistor bad
-Low Compression (Car Runs ok after 3K RPM Reached)

 

Sounds like you have all of the info you need. Time to start troubleshooting.

 

what arch said. check the cat too. 8s are not fast to start with, 4 port autos are even slower

 

Mistake 1: Buying an RX-8.
Mistake 2: Buying an RX-8 without a pre-purchase inspection that included a rotary-specific compression test.
Mistake 3: Buying an RX-8 with an automatic transmission without a pre-purchase inspection that included a rotary-specific compression test.

Get yourself an ELM327 bluetooth OBD-II adapter ($15 on Amazon) and a $10 phone app.
Clean your MAF sensor with MAF sensor cleaner.
Go over all of the vacuum hoses.
Make sure that the throttle body and upper intake manifold gaskets are present and in good shape.
Get a rotary-specific compression test done.
Check your plugs.
Check your ignition coils with an HEI coil tester (<$10 on Amazon).
Disconnect the catalytic converter from the exhaust manifold and have a look at the catalyst bed.

 

I can confirm that I did swap the MAF Sensor and it didn't change so I cleaned my old one and got my $90 back from AutoZone.
I can confirm the ThrottleBody and intake manifold gaskets still look brand new.
Coil Packs are good.
Spark Plugs are Good.

**Will disconnect the Catalytic Converter Later (If I remove converter will the throttle become erratic? Also I don't care about the noise.
**Will check all hoses **Whats the best way to check for leaks in hoses? What solution can I use
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Last test will be a Compression Test due to I have no time to take it to the shop

 

Sounds like a vacuum leak. I would do what Preppie said and get one of those OBD-II readers that have live sensor readings (I bought one for like $30 off ebay, I used the MaxiScan-KW808 on my rx8 and it works fine) and see what they are all doing at idle. A vacuum leak should show that the MAF is getting low voltage (since air is bypassing it into your motor). You will be able to look at all the other sensors to see if there are any obvious issues. Also, you may have a pending code which may point you in the right direction.

Worst case scenario is you scrap the current rx8 for $500 then buy another $1,500.00 rx8 off of craigslist.

 

I have Bosh OBD II .. I think my CAT is over heating from the live graph

 

Should we guess what temperature it's showing?

 

Do you have any compression numbers?

Also, for any AT, fluid health is critical. When was the fluid last changed?

And how do you drive the car? This car needs to be driven hard. It's not afraid of the redline, but low RPM will kill it(which is what the AT tends to do from what I have heard).

Still, 100 MPH should still be doable. Pretty sure that if I try hard enough, the 99 Corolla(120 BHP) I had could do it. The governors on the AT 8s don't kick in that early, either.

Removing the cat element doesn't mess with your throttle, but it will mess with your nose and possibly your bumper paint.

If you are talking about the vacuum hoses, there are different approaches. Some use carburetor cleaner and see if the car starts revving up when you spray a specific area. Others use a cloud machine/big vape and vape into the intake and see where the cloud/vapour leaks out.

Like how hot?

8 has a pretty high exhaust temperature compared to most cars, hence why some cheaper cats and resonators won't survive in the 8.

 

After I put seafoam in the car yesterday and it has sat and today it didn't stumble or boggled down. I drive my rx 8 hard all the time. The car transmission fluid light did come on.. tomorrow I will be driving it to and from work. From work I will use live graphs. Which options should I choose to record on the one ii so I can upload here? The Cat temp went from 800 degree Fahrenheit to 1600 degrees and it tend to drop on it's on during driving ..

 

1600F is the correct operating temperature for the catalytic converter.

 

Are you talking about the orange AT light? That indicates an issue with the auto trans.

I would start by checking and changing out the fluid since anything more than that can get pretty expensive.

And yes, 1600F sounds about right for the exhaust temperature if you drive the car hard.

 

Ok so my Transmission fluid is low I will change it tomorrow. Also my oil is new 5-20 Castrol GTX Conventional oil and my oil level hasn't changed and I have already done almost 1.5k miles. My oil look brand new when I checked it.. It hasn't changed in color or anything.. Should I use a catch can or Sohn adapter? I really love this car and I want it to last. I have 3 other cars but I really love this vehicle

 

For the oil, it depends on where you live. If you live somewhere hot, you might want to go XW-30 or XW-40, as heat can break down thinner oil.

Search up on the catch can and decide for yourself. Same for the Sohn adapter.

 

Your oil level should have changed by now, especially if you drive hard. You want to start premixing 2-stroke oil in the fuel until you're certain the oil injection system is working properly. A Sohn adapter and separate reservoir helps monitor the oil consumption, but it's not required.