Hi guys, im new here, but i resently bought a 2004 8 with close to 40k on a rebuilt engine and the previous owner gave me a great deal on it because he had it serviced and they told him something about a weak sensor in the engine. They said that there are three sensors all together and it would be best to replace all three. maybe he misunderstood them for the o2 sensors? i need some advice if anyone knows. Also, to fix the sensors and also a bad cat, they wanted to charge him close to 2K! sound about right?

Thanks for your help guys,
-RX 8 noob, Gunnar.

 

Is there a CEL on?

 

yes, its been on since i bought it about 2 weeks ago.

 

Get the codes read, then report back, we can't just guess what is wrong......

 

You need to get the DTC codes using an ODBII scanner. Where are you located?

 

Im near ATL, Ga

 

Apparently Autozone will scan your codes for you.

Post up the codes and we can point you in the right direction.

 

Okay will do! Thanks!

 

Even my crystal ball cant tell what code ur car is throwing, mmmm

 

got the codes! all 3 of em.

P0442
P0302
P0420

 

Do you have maintenance records for the car? I'll assume the worst for now

You have 1) A bad gas cap ($15 to $20), 2) You need to replace ignition coils ($180) (Maybe plugs($120) and wires too ($80)), and 3)your rear O2 sensor may be faulty ($150) or some small chance your cat is bad)

Do not drive the car hard until the coils are replaced. Buy them from a forum vendor.
All the codes are typical for an older RX-8 if it has not been maintained or updated.

I only estimated part cost. You can easily do all these yourself if you have some tools. There are other upgrade options such as BHR ignition with plugs ($560)

P0442 EVAP system leak detected (small leak) ON 2 EVAP system ´
(See DTC P0442 )
P0302 Rear rotor misfire detected Flash/ON 1 or 2 Misfire ´
P0420 Catalyst system efficiency below threshold ON 2 Catalyst ´
(See DTC P0420 )

 

P0302 is a misfire in the rear rotor.

P0420 is a common one, shows when the catalyst is dead or removed. Unlikely to go away, if you need a cat to pass state inspections it could be expensive, but the car also runs well without it.....

Misfire can be as simple as new plugs, (don't mix up the top and bottom plugs) basic maintenance on any used car.

P0442 is a small evap system leak, could be as simple as a loose or damaged gascap.

 

Misfire + cat trouble is not a great sign. Suggest you check/replace spark plugs, ignition coils and wires fairly quickly to be safe. Driving in this condition for an extended period could cause bigger problems.

Or if you're still under the 8 year /100,000 mi warranty, bring it in for a compression test, you may need/get a new engine.

 

Just got back from my local mazda dealership; after they inspected everything i was told that it was in deed the plugs, coils and wires. Got it all replaced for right around $750. Now i just need a new cat, but the mechanic also recommended straigh piping it since i live in a non emissions testing county! Thanks for all the advice guys, you were totally right.