- Misfires are shown by a blinking check engine light (CEL)
... and are usually caused by a failing coil, failing plug wire, and/or failing spark plug. They can also be caused by cat failure, engine failure, vacuum leaks, fouled e-shaft sensor, dirty MAF, missing intake screens, aftermarket intake, failing intake valve actuators and a few other items.
- The clutch pedal assembly is weak
... and over time the pivot points wear through the mounting points, and eventually this will cause a failure in the assembly. A squeaking clutch when you push it and release it signals the issue getting worse. Getting a new assembly only solves it till that one breaks. There are a few options for fixing it, including welding at your local shop, buying a bracket from Race Roots, or buying a fully welded up assembly from BHR. As a result of the NHTSA investigation, Mazda has extended the warranty on the clutch pedal assemblies to 100,000 miles in North America. If yours starts weakening or breaks, go see a dealer. If they don't believe you, bring your paperwork.
- Discolored or foamy substance on dipstick.
The oil collects moisture in colder ambient temperatures. You may notice that the dipstick will look like it has wierd discoloration. This has been discribed as foamy, milkshake, white crap, brown oil, etc... This is normal, and nothing of concern. If you want, you can pay a large chunk of money to make it go away, but there is no harm to it, so just ignore it. Drive your engine harder to cook it off if it bothers you.
- Oil in the Intake:
Oil in the intake can be caused by a few different factors, including: Not using a long neck funnel when adding oil (allows oil to drain through the oil filler neck's vacuum line), a vacuum line connection problem that does not adequately vent the oil pan's pressure, and overfilling the oil pan. Oil getting into the intake can lead to problems with the intake valving getting gummed up or carboned up, and can also cause stumbling, misfires, and fouled plugs if blobs of oil are ingested from the intake with the engine running. Many owners install a catch can to help prevent these problems.
- MAIC, or "Marbles in a Can"
... is a fortunately not common issue where you may hear a rattling sound from what sounds like the glovebox area, sometimes accompanied by inconsistent power loss. This is usually Secondary Shutter Valve (SSV) failure, which is typically caused by the valve getting over carboned, from oil burping or oil excessive oil vapors in the intake. Dealers will charge $2,000 or so to replace/clean, but you can DIY it for pretty much free.
- Power Steering:
Mazda's QC missed a little issue with the coolant overflow tube, as it dumps overflow right onto our power steering connectors (the main power and torque sensor connections). Even without an "overheat" condition, overflow is possible, which in turn can affect the condition of these connections, causing various power steering issues, including complete failure. Then there are other issues that can crop up, including too much salt, dust, or debris interferring with the grease on the u-joint in the steering shaft, rack failure, and control module failure. The u-joint re-greasing is dirt cheap, easy to DIY, the connector fixing is even easier (clean, replace harness for $100, or eliminate the connections and just make it solid wire). The rack and control module are REALLY expensive however. Most power steering issues were addressed by dealers replacing the module or the rack, when all the car needed was some clean connectors. Ideally, swap the coolant overflow hose to a longer one and run it farther down, where it won't bother anything.
- Faulty Coolant Level Sensor:
The coolant level sensor in the coolant bottle is prone to failure, allowing the float to sink to the bottom of the coolant bottle regardless of how much coolant is in the bottle. If your coolant level light comes on below 7,500 RPM, and you have sufficient coolant in the bottle, then the coolant float is water logged. Fixing this requires replacing the coolant bottle, since the sensor and float are integrated into the bottle. Mazmart.com has a replacement bottle for relatively cheap. If the light comes on above 7,500rpm only, then you may be experiencing a cooling system failure that is creating a restriction and/or water pump cavitation instead.
Caution: There is a small hose from the bottom front of the coolant bottle to the top of the radiator. If you have an OEM or OEM replacement radiator with more than ~40,000 miles on it, you are EXTREMELY likely to break the nipple off of the radiator instead of sliding the little hose off. If you break it you MUST replace the radiator. It is recommended to buy a replacement small hose and cut the current one off carefully. You can not underestimate how easy it is to break. Many of us (me included) thought we could get it, but ended up breaking it anyway. The radiator nipple is EXTREMELY fragile.
- Weak Starter:
On 2004 and early 2005 models, the starter was pretty weak. Mid 2005, Mazda upgraded the starter that they use, and it works pretty well, and lasts quite a while. The 2004 and some 2005 starter upgrades WERE free, but the owner had to do something about it with the dealer. It was NOT a recall. So if you have a 2004 or 2005, it is entirely possible that you still have the original, and very weak, starter. The Bumper to Bumper warranties that would have covered these is long since expired, so if you want to upgrade, it's going to beout of pocker. Additionally, just because you have the upgraded starter, doesn't mean that the upgraded starter is bullet proof. Don't rule out a starter problem "just because you have the upgraded starter". They don't last forever. It can and will fail eventually, just like any other car, and replacing a weak or dying starter is still a fact of life for every car that relies on one.
- Motor Mounts:
Our motor mounts collapse/degrade over time. This causes the car to shake more, especially at idle. This isn't the actual engine attachment points, but rather just the vibration dampeners. However it is not inherently a problem that you need to rush out and fix. Adding more vibration to the car isn't inherently bad, but can lead to other problems with rattles and joints wearing down. Most people choose to live with it. If you are getting a lot of shaking and vibration at idle, but the tachometer needle is stable, then motor mounts should be the first thing looked at for a solution.
- Catalytic Converter Failure:
This is too common unfortunately, as the heat and emissions level of the RX-8s engine is not friendly to cats at all. Additionally, most of the encountered failure points on an RX-8 cause misfires, and misfires will destroy a cat quickly. When the cat clogs, there will be localized heat buildup, a capping effect on total power, and other components will start being stressed to the point of damage. These include damaging and destroying O2 sensors and engine seals. Eventually, if ignored, a clogged cat will cap power output to under 20-30hp, not enough to even maintain highway speed. If the clog is this bad, you are already well into engine damage range. If the clog is STILL ignored, it can eventually start a car fire that will melt your car to the ground. Hopefully without you or your friends or family in it. A clogged cat is dangerous to the engine, the car, and your life.
- Trouble starting:
There are numerous things that cause you to have difficulty starting, and many of those problems are similar to the problems above. Once you have a problem that makes starting harder though, you are immediately at risk of flooding, which will take you all the way to being unable to start. Keep up with other maintenance and repairs, and this won't ever be an issue.
- Dash Cluster flickering or jumping crazily:
If your dash cluster gauges are flickering, jumping, spazing out, going crazy, or any similar description, and the car is off, then your battery connections are heavily corroded, and need to be cleaned. Disconnect the negative cable, then the positive cable, clean the battery posts and the cable clamps thoroughly. Reconnect the positive than the negative, making sure that the clamps are seated firmly on the battery posts before you tighten down the clamp bolts.
- Stalling after Battery Disconnection:
When you disconnect the battery, it clears all fuel trims from the ECU, which need to be relearned. There isn't much of a driveability impact in gear and driving, but it can disrupt the idle stability significantly, some cars may even stall from having fuel trims too far off from what the ECU's base fueling is and the ECU can't 'catch' the revs falling idle accurately enough. It is recommended that after reconnecting the battery, you let the engine idle for about 10 minutes before driving. This will smooth out the idle fuel trims and remove most of the idle instability.
- Air Box Grommets Block Fans:
The rubber grommets that the stock air box uses can pop off from time to time, usually when you are working on something else, and too frequently they will fall into the radiator fans just below, jamming one of the fans. This usually results in a blown fan fuse, as well as overheating when not moving. Check the grommets when you are moving the air box, and if you have a fan that isn't working, look for a grommet jamming it.
- Royal Purple Transmission Fluid:
Don't use it. Too many new owners change the fluid to Royal Purple brand and like to feel cool about it, and they do, for a few thousand miles before the transmission syncros self destruct. Royal Purple is a popular brand that has a lot of marketing behind it, but they do not make a transmission oil that is compatible with the RX-8's transmission, and it WILL destroy your syncros
- Water in the tailights
Primarily a 2004 and 2005 problem, but can be seen across all years, including Series2, is a failing tail light gasket that lets moisture into the tail light lens. The improved gasket from the dealer helps, but isn't perfect. You have options for repair, including DIY stuff and aftermarket gaskets. Drilling the tail light is a quick and easy solution, but is not recommended.