I bought an rx8 a few days ago when I looked at it it started fine and ran fine but on the way home it started to loss power and then it would have power and sometimes while it's idling it will idle find and some other times it will die and when it's hot it won't start but when it's cold it will every time I just replaced the plugs and wires going tomorrow to get ignition coils to see if that fixes it but I don't wanna keep putting money into it and not fixing the problem

 

Did you get a compression test before buying it? That may be playing into it, plus it would tell you if the engine is worth investing into.

 

Compression test my friend! So that u know the condition of ur engine, then u know prolly know what to do from there.

 

I'm going to do that today

 

Btw, u should search up on rotary engine compression test (dont get a normal compression test)

should get 3 readings for each face per rotor normalized to 250rpms.

 

Doing a compression test will eliminate the biggest and most expensive variable in the diagnostic chart. Doing a compression test before purchase is the best thing you can do. If you are going to stay in the rotary game, I recommend a rotary compression tester from www.rotarycompressiontester.com. I bought one and it has been one of the best tool investments that I've made to date!

 

It will start when its warm when you put jumper cables on it but not with out them

 

Ah you might have a bad cell in the battery causing the starter to turn slower than normal. Get that compression test, but test/replace the battery too.

 

Yeah, that's a good possibility. These cars are brutal to batteries due to engine bay heat. Don't expect a battery to last more than 2 or 3 years. My car is 6 years old, and it has already eaten its OE battery, 2 Optima Red Tops, and is working on killing a NAPA Legend.

 

That's crazy. Mine is 13 years old and I've only changed the battery once, to replace the OE Panasonic.

 

To be fair, Optima Red Tops suck, so I guess I can't hold that against the car.

 

But I still don't know why it dies at idel

 

Get OBD data for short term fuel trim, long term fuel and airflow at idle, especially when it stalls. It may point to a vacuum leak. But still get that compression test, it could also be responsible.

 

I did that and p0302 p0172 p0610 and p0420

 

OK those are the codes that point to your car running very rich (potentially the coils are not working), but it's not exactly what we need.

We need the sensor data for airflow (in g/sec or lb/min), and short term fuel trim % and long term fuel trim %. You should be able to get it the same way you got the codes.

It sounds to me like you have an ignition problem, a vacuum leak and potentially a clogged catalytic converter and the P0610 is some other weird kind of beast altogether.

 

Definitely check the compression.

Replace the battery as well, and if your RX-8 is from 04 and 05, replacing the starter with the one from later years will also help.

STFT and LTFT should be between +10% and -10%, and their sum should be between those two numbers as well.

There is also the fact that you live in Texas, while I and Loki live in the Great White North.

When I got my 8, it had a Panasonic, presumably OEM. I replaced it because it is a bit slow at times and it's old, but it's still not quite dead. The Eliminator Ultra AGM battery I got from Canadian Tire also comes with a 5-year warranty, so I've got nothing to worry about.