Zach21035

I apologize in advance if this is already answered, I've tried using the search function to no avail. Also, I apologize for this epic first post, but I'm desperate and won't be able to get the car to a mechanic for some days now.

Some background on my car - 2004 RX-8, 97k miles, on it's first engine. Purchased used at around 45k back in 07. No major service that I'm aware, unknown if the previous owner had any issues (purchase with a one year warranty but no maintenance records). Regular oil changes at around 5k miles a piece (I know Jiffy Lube says 3k, and if this is what killed my car, I'm doing daily oil changes the rest of my life) and no major issues with it, other than a somewhat obnoxious but relatively quiet rattle which I was told by two seperate mechanics was just a loose heat shield. CEL came on around 1k miles ago, and the car was looked at by one of those "friend of a friend" mechanics who just pulled the error code and told me to replace the spark plugs. I should note that before this "incident", I had not driven the car other than short hops for a few weeks, as I've been using my other vehicle for commuting due to gas prices to save money since my girlfriend was recently laid off.

Now, as you can probably tell from above, I'm not a car guy, but I'm pretty handy with tools so I figured I'd do it myself. I've read about the ignition coil issue and figured I'd take care of that while I did the plugs, and my air filters were overdue for replacement so I did new cabin air filters and put in a K&N air filter. Used the DIY Ignition Coils posted here to the letter, Topped off engine coolant while I was at it. I will note I used ignition coils from autozone since I remember reading here that they're equivalent to the Mazda ignition coils. 4 hours of fooling around with the spark plugs later in 100 degree weather, I felt pretty satisfied with myself. The old plugs were filthy and the ignition coils had the large white marks on the bottom that I've read are a sign of failure. I eagerly started up the car...

After a false start (I guess it's a hard start the first time after replacing the coils?) CEL went away as promised. The car also has a deeper, sportier sounding pickup that I guess is from the new air filter. However, after about 5 miles of driving on back roads, I noticed that the car seemed a little more... sluggish than usual. Nothing serious, and it still picks up pretty good even at low rpm, which it had trouble with before, but as I started hitting around 4k I noticed it wasn't putting out as much power as before. Then the fun started. After a few more miles of driving at lowish rpm just to ease into it, I decided to rev it up a bit. The sound can only be described as what nightmares are made of. Around 5-6k rpm, I heard a chattering/scraping sound. No idea how to describe it. Mid to high pitch, almost like electrical arcing combined with gears grinding. I backed off the throttle immediately and it stopped, though it was repeatable just by giving it gas in the 5-6k rpm range. I also noticed that there wasn't anywhere near as much power in that range as usual, though I'm too terrified to keep going to see if it continues through the whole rpm range.

Immediately turned around to bring it back to my friends house where we had been doing the work. The radiator light came on several times and would not go away until I upshifted to lower rpm - this happened at any kind of sustained driving at around 4k rpm and went away within seconds of slowing down or upshifting. Temperature gauge remained normal throughout, slightly to the left of middle. Car continued to feel sluggish. CEL came back on at around 25 miles after being restarted.

Since then, I've put about 70 miles on the car. The horrible noise at high rpm continues, and seems more likely to occur after the car has been driven a bit (it's about 5 miles from my apartment to the highway then about 20 highway miles to work). It still feels sluggish, almost less powerful than before I replaced coils and plugs. I'm not noticing any odd odors, difficulty starting, or other noises other than the rattle that's been there since I got the car. Car idles smoothly at around 950 rpm. As long as I keep it at low rpm, I avoid the radiator light and rattle, but I might as well just be driving a Prius and the CEL still worries me.

Again, I apologize for the long post, but I'm desperate. I'm not going to be able to get to a mechanic until Monday and my girlfriend is out of town for the weekend with the other vehicle. Mostly I'm concerned about whether the car is even safe to be driving right now, though obviously I'd prefer a detailed diagnosis, preferably one that isn't "You put your spark plugs in backwards, moron". I'd prefer not to catch on fire in the middle of 295.

The "I didn't read all that" version - car ran fine but had CEL. Replaced coils, plugs, air filter. Now have radiator light and demonic chattering sound at high RPM. CEL went away but came back with a vengeance.

For anyone who didn't give up after the second paragraph, I thank you in advance. If nobody knows what the hell I did to my poor little car, I'll follow up with the offical diagnosis from the mechanic so we all may learn by my suffering.

kma5783

iTrader: (7)

First thing you should do is get the CEL scanned at your local auto parts store, they should do it for free then post the code here for us to try and help.

Zach21035

Copy that. I'm going to be hitting up Autozone on Sunday, though I have to drive the car into work tomorrow. I'll follow up with the error code/photos of the flame engulfed husk of my former car. Either way, it should be good times for all.

kma5783

iTrader: (7)

Car should be ok since you said you're only experiencing the noise around 5-6k rpm so I would definitely keep it below that until you can figure out what your issue is. Also if possible a video of the noise your experiencing may help but I would start with just getting the CEL scanned.

Easy_E1

iTrader: (2)

Make sure your plug wires are going from the correct coil to the correct sparkplug.
Do you still have the factory Catalytic converter on the car? If so see if it's exceptionally hot or glowing in the dark. Bad coils over a period of time can cause Cat failure with all the misfiring,
The coolant light is a failure of the sensor in the coolant overflow tank. It's very common.

rafaga

iTrader: (1)

what type of spark plugs did you use? This engine is very particular about that. And as easy said, make sure the wiring is correct.

Mazurfer

Yeah, Easy's right....first check that wires are going to the right place.
Then make sure that wires are making good contact to the plugs, you should feel a little snap or click when you are putting the wires on the plugs.




I was also wondering about the CAT. As also stated , take it for a drive at night, then after parking, look under the drivers side of the car and see it's glowing red.

Coolant light sensor not a big deal given exactly what you have described(that's the "normal" failure mode symptom for this). Your choices are either to replace the bottle or unplug the sensor(see below) and just monitor your coolant level..................which you should be doing on a weekly basis anyway.

Zach21035

Hit up the local autozone and got the codes pulled. I'm getting p0171 (Lean Air/Fuel ratio bank 1), p2096 (Target AF feedback system too lean - right bank), and p0456 (EVAP control system leak detected - very small leak). Not terribly happy to seem "Engine Mechanical Condition" as a possible cause of the 0171.

As for the car itself, I've noticed it seems to be related to runtime. I don't encounter issues getting out to the highway or driving to the city, but the return trip is when I start running into issues after crusing down 295 at 70mph for about 20 miles. It's once I get back onto the city streets that it seems to have issues. The sound remains and kicks in around 4500-5000 rpm after the car has been running for a while. I've heard the phrase "marbles in a tin can" mentioned before - I'd describe the sound as a tin can full of marbles being tasered.

Same thing with the sluggishness - acceleration is normal when I first start driving the car and gradually gets worse to the point that on the trip back from Autozone and a little old lady in a Buick was pulling past me at lights. On the highway, acceleration is so poor I have to downshift to 5th to maintain speed on even a gradual incline.

I used the NGK Iridium spark plugs and Duralast ignition coils from Autozone. Checked the wiring last night, everything seemed kosher. Unless I'm completely missing something, but I traced each wire from coil to plug.

I'm not seeing a glow from anything under the car, though to be honest I'm not 100% sure on where to look. I do hear a popping sound after the car is driven for distance and then parked - sounds almost like sizzling bacon and will occur even if the car is still cool enough that the hood fan doesn't kick in.

Any help would be appreciated. It's starting to look like something that's going to be far beyond my ability to repair. At this point, I'm more concerned about how much this is going to cost me at the shop rather than if it's something I can ignore.

On the plus side, the engine coolant sensor has apparently decided to behave itself (or some good samaritan unplugged it for me) since I haven't had an issue with it for a few days now. Always look on the bright side of life/catastrophic car failure!

Lord ET

iTrader: (1)

For the p0456 try clicking the gas cap like 5-10 times instead of just once or twice. I crank mine down a couple of turns. It's a known issue and the gas cap can be replaced. Assuming that's what the issue is. Try that, clear the code and see if it comes back on after a while.

Rote8

Hmmmm, nobody touched the scary one....

"I decided to rev it up a bit. The sound can only be described as what nightmares are made of. Around 5-6k rpm, I heard a chattering/scraping sound"

You are at 97,000 miles; I would get a compression test before crossing 100,000 miles, you may get a new engine, if the engine is damaged. (the warranty on most RX8 engines is 100,000 miles)

A simple back yard test is to disconnect the coils from the ECU, and remove the two lead spark plugs. Spin the engine and listen for 30 seconds of cranking time.
Do the sound pulses sound even?

Listen for spurt, spurt, spurt. puff, spurt, spurt spurt.....
Any weaker sound than the rest of the sounds is bad.

If it sounds uneven, see your dealer for a real compression test.