First off, I'm gonna go ahead and say that I have never used this website, so I'm not even sure if I am doing this correctly. I'm not sure if I'm posting this at the right place. Anyways, I own a 2004 automatic RX-8 and it has been giving me major issues. It will randomly just shut down on me when I come to a stop. It never shuts down unless I stop. It isn't getting overheated and I keep up with the oil. I have no idea whats causing this. The RPM just randomly dips below one and then goes to zero. Quietly it just turns off completely. And when It starts back up it has no power what so ever. It cant make it up a hill. II tried to come up my road yesterday after i had gotten it started back up and it simply couldn't make it up the hill without losing so much power it shut off. Does anyone know what it could be?? Ive replaced the coil packs and spark plugs. I hooked it up to a computer and it said that the manifold tuning valve was stuck open and I fixed that. nothing is seeming to help

 

Any other check engine lights?

It could potentially be a dead engine. How many miles are on it? Any other symptoms? How long has it been like this?

 

Possibilities:
- Severely clogged cat
- ESS fouled, ESS needs resetting
- MAF fouled
- front O2 failure
- Fuel trims off

 

I concur with the recommendations...

Clean MAF, Clean ESS, there are DIY's in the $100 thread below.

I would also do star washers on the grounds, that is the easy version of the grounding kit.

that cleans up the electronics for about $10 and a few hours of work. Then 20 brake stomp process to clear ECU and start it, let it idle until is warms up completely.

At least, that is what I would do.

 

Also, vacuum leak (disconnected or broken intake parts)

 

Thanks for all your all's input, I really appreciate it! I didn't even expect to get replies to this post. this is apparently a very good website. After rehooking it up to a computer, it read that the o2 sensor was bad. Me and my brother suspected that it could be reading bad due to bad spark plugs and coil packs. Replacing those things helped the car in general, but it still is breaking down. Another symptom i forgot to mention is that after it breaks down it is really hard to start back up. It cranks and cranks and cranks. If i let it sit for about 10 or 15 minutes it'll finally starts back up but it is extremely weak and hesitates to accelerate. As long as i get it up to speed it runs like a charm, but as son as I stop or slow down it will lose power and stop. before it breaks down the entire middle console gets really hot. could this be a bad catalytic converter? And maybe that is making the o2 sensor read bad?

 

Get the compression test man, the engine could be shot and you could be wasting time and money replacing things that won't help anyway.

 

Yeah, get your compression checked before investing anymore money into it.
In the meantime, you can drop your cat and inspect it.
I'm not sure if a bad 02 sensor code comes from a bad cat, but it could be making the cat hot.
When my cat was bad I had a misfire code from a bad coil & cat below threshold code, the cat had been damaged from the misfire. But it never died on me, it would lose power at high RPM & get a flashing CEL.