rotard26

I replaced the plugs and wires with oem NGK's after getting a p300 misfire code but not the coils. It's a used 2005 base model 1.3 Liter automatic with a rear spoiler mod. It was running great for the longest time. As soon as I moved back from the eternal summer that is Florida to arctic rush Missouri winter it was running rough and vibrating vigourously and the revs were unusually high they would die down and spike up a little. Exhuast emissions were crude and billowing out like a tobogan. first thought was a cold weather induced drastic temperature change with the MAF sensor or am oxygen air intake sensor in the vacuum messing with the manifold amd detecting less availaibe air. Eventually,I got the codes ran and got a random misfire code. However, the problem still persists. No telling what it is until it gets looked at by a reputable mechanic shop. I think it's the coils but i dont have money to burn and the know how to trouble shoot it. It was running better when the weather was warmer as if it were shivering. It might need a compression test. The battery is low in crank power but its still cold starting up farely well also the air filter is new.
I take care of it cosmetically and in the interior with regular washes and occasional leather seat shampooing/conditioning vacuimg head light restoratiom kit,windshield cleaner, meguiars quick wax and self serve car washes with the shams and terry towels. It has a cracked front bumper and compoments and poorly applied touch up paint.
Saving up to buy the parts after fixing the engime problem. Going for a used oem black bumper cover on ebay and the other parts from a factory mazda store. Then paying for installation. So im estimating around 1000.
I know this is a somewhat common problem with the vehicle. Are any of you experiencing Or have experienced the same thing?
Having second thoughts on getting this car. What would you recommend? If you have any questioms just ask.

Jedi54

iTrader: (7)

do you feel the vibrations when at a stop or when moving at speed?
does the vibration / shivering happen constantly or is it on and off?
I wonder if this could be as simple as some bad motor mounts.
have you checked the catalytic converter to ensure it isn't clogged?

rotard26

it shudders only when in 1st or in reverse and sometimes worse than others. It's on and off. I only checked underneath after a long drive and it wasn't red ( a tell tale sign of it being clogged) but i havent had anyone look at it yet. Apprently to get a dtc or ecu at a mazda dealership is 160. I was surprised it wasnt free. I thought they would give a more precise diagnosis since they have an ecu module mazda brand computer instrumemt software vs one at lets say an autozone or any commercial sales autoparts store.

Loki

iTrader: (1)

The code readers output roughly the same information, so in 95℅ of cases, AutoZone will give you the same info as Mazda

Invest in coils if you don't know how old your current ones are and you want to keep the car. They are the number one killer of engines.

Does it warm start without problems?

You may have a vacuum leak as well, but start with coils.

rotard26

Youre not tricking me are you Loki? Jk haha.
Thanks. That's what my brother said. He's a BMW car guy fanatic. Sorry If I'm posting like an idiot. Luckily they're not too expensive. I'm not good at installations no matter how easy. I guess I'll find someone to help swap out the old ones. He has friends that have worked on RX8's. Thanks.

gwilliams6

You have a number of options for coils:
- The Cheapest option: BWD/Intermotor coils from auto parts stores like Advance Auto. 4 coils, 4 plugs, and 4 wires can be had for around $190-220 total based on whatever promotion is running at the time, shipped to your door for free. They are considered to be the first coil revision and you should expect to need to replace them around 20,000 miles, 30,000 miles max. They often come with a "lifetime warranty" by the auto parts store, which could potentially be leveraged for perpetually new coils.

- The Best Upgrade: The BHR ignition coil upgrade can be had for around $500, which eliminates the need to continue replacing coils periodically, as well as deliverying a significantly stronger spark for minor mileage and power gains. It is a proven kit with top notch customer service supporting it. It includes the wires, you still need to add plugs ($80)

- The For-Sure OEM: Mazmart sells all 4 coils of the latest OEM coil revision (C) for around $250, (just the coils, you still need to add plugs and wires) Supported by top notch customer service. They will likely last longer than 30,000 miles, but we don't have much solid data on how long the latest coil revision will last.

- The Most Expensive option: Buying from a dealer will run you around $300+ for the coils, $500+ for coils, wires and plugs, and if you have them do the install, expect to get a bill for anywhere from $700 to $1,800. You may not get the latest coil revision. Yes, you are getting shafted if you take this option, so bring lube.

- The Highest Risk option: Ebay coils continue to pop up as counterfeit, mislabeled, dead on arrival, and have zero post-purchase support largely. They are the "cheapest" listed price, but when you add that $92 or whatever to the price of anything in the list above from having to do it over again, you can see that they are no longer the cheapest option. Do it right the first time. "Motor King" coils are popping up at an attractive price on Ebay, but are being proven as ineffective, to the point of being unable to get the engine fired. "Mazda" branded coils on ebay are almost always counterfeit. Check the seller's name though, since some of our vendors sell legitimate coils there. The price will be $200+ though. Anything sold as "Mazda OEM" under ~$26 per coil should really be considered as suspect and probably counterfeit.

Be wary of "LSx D585 coil upgrades", as not all D585 coils are created the same, and the standard generic D585 coil is not properly designed internally for the RX-8's ignition needs. They generally "work", but there are anomalies and performance issues that have to be solved, if they can be solved. Definitely NOT a plug and play option, even if it is advertised as "plug and play"

GB: SakeBomb Garage IGN-1A Ignition Coil Kit
________________________________________

rotard26

You are awesome. -very thorough
I replaced the plugs and wires just not the coils yet. Rx series can be such problem childs.but rotaries are so smooth and 9000 revs.. You cant beat that. Let's hope that's the solution and not engine mounts. Should I put in a few hundred miles to get it adjusted or still baby it and play it safe? I'll get it looked at by a professional. Haha if it werent for this and the minor front bumper components damage, i'd be investing in some mods like window tint and wheels to start then exhaust. Priority 1 of course is to fix the engine problem 2 is repair front bumper components and touch up paint then a few performance mods.
Thanks for the feedback. -very informative and helpful.

gwilliams6

Don't wait on those coils. As Loki says, bad coils are the number one killer of rotary engines and cats. And it doesn't take long running on bad coils to cause cascading permanent damage.