Rough idle, loss of power
 

Hey guys, I'll start with my stats: 2005 RX8, 103xxx miles, I bought it around 93xxx, and I've had it for about 10 months now. I have a service plan with the dealership where I bought it, so I've had the oil changed every 5k. But other than that, I pretty much know nothing about cars.

Currently my 8 is having trouble. CEL is blinking. It idles rough, shaking more than usual, and it sits at about 700rpm idle. If I try to drive it, the acceleration has almost zero power, and the engine still shakes. I have to keep the rpms pretty high to get anywhere. I've only driven it probably a total of <10 miles since this started, over the span of 4 different trips. One trip was to AutoZone, where I had them read the CEL code, and we came up with:

P0171 (lean air/fuel ratio bank 1)
probable causes:
1 - low fuel pressure
2 - large vacuum leak
3 - dirty/defective maf sensor
4 - engine mechanical condition

and P0301 (cylinder 1 misfire condition detected)
probable causes:
1 - lean air/fuel ratio
2 - weak ignition system
3 - engine mechanical condition
4 - vacuum leak affecting one cylinder

I found another thread from a very well-informed poster, and it seems that his symptoms are the same as mine, except it seems his condition comes and goes. Mine seems to want to stay.

https://www.rx8club.com/trouble-shoo...ou-can-206369/

My main issue is that everything seems like a different language to me :banghead: -- I need someone to dumb it down. any help would be great! thanks

TheAgemaWay

A flashing CEL is ALWAYS a misfire. Every single time. It's hard coded into the ECU.

Many things can cause misfires. Fortunately, there is a thread detailing out how to address each in order to figure it out.

https://www.rx8club.com/tech-garage-...t-here-222280/

And misfires will cause both lean and rich conditions, to the point of sometimes throwing one code or the other. Misfires will also lead to cat damage, O2 sensor damage (both front and rear), engine damage, and eventually can light the bottom of your car on fire. Highly recommend not delaying in solving it.

Chances are your ignition is shot, as our coils/plugs/wires fail on average about every 30,000 miles.

this is perfect! thanks!

I tried cleaning the MAF sensor first. It was pretty much black. Maybe my hopes were just high, but the engine DID sound better after that was clean. Still misfiring though.

I wish I had the money for the BHR set that FungsterRacing recommends. But I was able to get new coils, wires, and plugs on advanceautoparts for just over $200. I have them on order, and hopefully they'll be here in a couple days, and I'll post an update.

I appreciate the help :)

Did the coils and plugs help? Mine was towed home tonight for this exact same thing. Was running perfect and the all of a sudden she lost power. Idled rough and sounded like a tractor , and eventually died. I'm not sure what to do. I'm afraid I lost compression :(

Mod edit: This post was merged over from another thread, he posted all over the forums, and this thread is the only one with replies so far, but this post from another thread is the only one with more detail

I had my coils replaced also expecting to have the car back on top shape (my car seems to loose power after driving it for more than 20-30 Kms). Mazda dealer said this problem is fixed by replacing the coils which was not the case.

So I had done a compression test on another Mazda dealer and result is that the car is not that bad. Is not new but is still acceptable.

Went back to the original dealer and after contacting Mazda they claim is an engine issue and is the 'beginning of the end' their own words.

I had spent more than 600Eur and I still have the problem :((( I heard they are willing to get the car fixed yes with a new engine. Apparently is very usual to buy a car, always do the maintenance on the dealer and then replace the engine on 100K!!!!!

I have the same problem. My compression does not show a very black scenario but for the dealer solution is replacing the engine!!!

Any solution that you ve come to that I can check also?

All my research Fernando is pointing towards my 8 having lost compression. Probably a side seal is my guess. But Idk for sure.

Suddenly sounded like a tractor = dead. Pretty specific sign

I figured J86

Lol thanks for the clarification

I do not have the tractor sound so I am still planning to make a 1000KM trip with the car praying that it does not break. My car while cold mid hot has no trouble at all but after being hot then the car is not the same.

Fernando, you are not being very clear with what symptoms you have. If you would like some help and advice from us, I suggest you give us some detail on what you are experiencing.

Sorry I will try to describe it the best I can.

Starting the car from cold is OK. Fast start, rpms go high between 2k and 3k and then settles down. If I drive the car to my work around 15KM distance I do not notice any problem.

However when travelling for more distance when the car is already good hot, I notice a lack of power. I say lack of power because acceleration becomes more difficult (rpms take a lot of time to go high comparing to the normal scenario). Also if I stop on a stoplight, when I start from 1st gear it takes more effort and also I kind notice a different working sound from the engine. Also when I stop and let it idle, it is not constant around 900-800rpm but sometimes goes lower and I hear a metalic sound coming from the engine.

Starting the car from HOT is still acceptable it takes 1-2 seconds more than on cold condition but always starts on the first attempt.

When the car is hot and with the noticeable loss of power, if I use higher rpms than 4k i see the Coolant light coming up which is known issue but there is plenty of coolant available. Sometimes I also see the Engine Problem Yellow light but very rarely.

Mazda replaced my coils but behavior is the same. Now they say it is an engine problem. I have done a compression test but still the results are not that bad that I have to replace the engine right away. Later on I can add the compression test done so I can have your opinion on it.

My main concern now is that I am doing a 1000KM journey to Norway and I just hope to not have any problems. I will drive slowly and not go higher than 3k. Also I will be stopping every 2 hours so the car cools down.

Hello, have you checked to see if your catalytic converter is clogged?

By the Engine Problem Yellow Light you mean the Check Engine Light (CEL) and if it lights up even if it's very rarely, it might mean some more fundamental problem with the engine.

My 2006 RX-8 's engine is at 35.000km, and it never made hot start or hot working problems nor have I ever seen the CEL light up.

In my car, the only problem was about the cold starts and to find the cause of it I replaced all ignition parts (sparks, cables, IG coils and even the battery) to rule out the cause of it and now there are only 2 possible causes left: Bad quality of engine oil or the starter has gone bad. Now I will replace the oil and see if it solves the cold start problem.

If I were you, I would first solve that problem with a similar approach (elimination of possible causes one by one) and see if it will help. And only then would I consider driving the car for long distances.

Big Cajun has the right direction, I would bet that you DID have coil failure, but it was ignored long enough that the misfires clogged your catalytic converter, and now you have a clogged cat. The symptoms sound dead on what a clogged cat will do. It feels good when first starting, but slowly the maximum power you can put out keeps dropping farther and farther as the pressure of the exhaust builds up more and more before the clog in the cat, making the engine work harder and harder just trying to get the exhaust out, leaving less and less for the wheels. Lower RPM driving keeps this at bay more, higher RPM driving will bring it on faster.

Continuing to drive it like this WILL lead to engine damage, sensor damage, and eventually a car fire. Get the cat replaced, gut the cat, or replace it with a midpipe.

The CEL codes are all emissions related. It could be more accurately described as a "Check Emissions Light". If you look through the CEL code list, some of them relate to the engine, but ALL of them relate to emissions. A poor running engine is a drop in emissions, so some of them do cover engine performance problems, namely O2 sensor problems and misfires.

There is absolutely NO possible way that oil quality is causing Fernando's problems. Oil will continue to do it's job right up until it has lost viscosity, at which point it will start accelerating engine wear until the engine seizes. It won't inherently cause a loss of power by itself until the engine physically can't rotate any more.

Cold start problems are typically either a fuel system pressure problem (a leak somewhere bleeds off the fuel system pressure while it sits, and adds time to starting as the system has to re-pressurize), a battery problem (which you addressed), or a coolant seal failure (because coolant has collected in the housing while it sat, and it has to get swept out before the engine will fire)

Sorry to revive an older thread, but it looks like there is already a lot of information here so no sense in starting a brand new one.

2006 GT - 6 speed Auto - ~90k miles

I'm not sure if it's relevant to the topic, but I do have the Turbo XS mid pipe and exhaust combo.

I noticed on hot days after driving for 15-20 minutes that the car had a really hard time keeping the rpms up on the interstate. I usually do 70-75mph a little above 3k in 5th gear. I would notice when we hit hills or traffic started moving slow enough to bring the rpms under 3k that it would just slowly die off until I shifted down to 4, then all seemed well once I got it back up to speed. also rough idle at stop lights. it would drop really low and run roughly, then jump back up and be ok for a minute.

I read around and it sounded similar to fuel starvation so I started filling up at 1/2 tank instead of 1/4 and the problems continued.

Plugs/wires/coil replaced 2-3k miles ago.

Today on my way home, It flashed the oil filter light for a minute. It went away relatively quickly. I was about 10 minutes away from home so I thought I would just get there then check it out.

As soon as I got into town I was driving along like normal, 3rd gear then I believe the engine seized up. I had a sudden complete loss of power and a big cloud of white/grey smoke. I threw it in neutral and made sure the engine was off while I rolled it into the nearest parking lot.

As soon as I got the car stopped I looked under it and it was draining a milky substance that looks like a combination of coolant and oil. It drained until I was completely out of coolant. I haven't had a chance to see exactly where it was coming from, but it did somehow make it into the intake. I'm assuming the big cloud was my engine burning out the oil that it sucked in.

So give it to me straight. Does this sound like I'll be replacing the engine? And possibly radiator?

In all honesty it sounds like you blew seals. Pics would be better to try n diagnose.

will do.. car is parked at my parents house for the night. I'll dig in there and try to get some pictures this weekend.

Thanks for the reply

Going back to this thread to say that I did replace the cat and ignition system and still same issue remains. Now direction is checking the O2 sensors. There is no error message on the ECU so is hard to say what it is.

Anyway I had opened a new thread in the new member area reporting on my personal case.

ok, been looking at a lot of threads and it seems like there is a lot of potential problems that touch on the symptoms im having. maybe thats because theres not much to go on and I might be catching this early. but here goes...

2005 6 mt 57k miles, second owner but first owner kept the car up to date on scheduled pm's.
symptoms: rough idle when engine is warm, idles around 750rpm, and noticeable vibrations. also, a CEL flashes when the car gets up around 6.5k rpm.

driven less thn 20mi since I first noticed this. also just got the car back from an autobody shop, after my 8 was hit in a parking lot, and had to replace some small things in the front end.

where should I start with this?

here goes..

2003 rx8 91k miles,

never had a hot start problem in my ownership, drove really well,
until.... last night i was driving her hard, red line up through the gears then the missus said to slow down so i did, as i was letting the car slow down i saw the eml flashing, then after about 1/2 a mile i heard a different tone from the engine and loss of power so pulled up at some lights and turned her off.. then tried to restart her but wouldnt.... sounded like she was flooded, left her 5 mins and tried to start again and she did but was running as rough as a badgers backside... limped her home not being able to get much speed or revs out of her, every set of lights i had to fettle the throttle to stop her from stalling. if i was changing down it was stalling so had to bump on the run to keep her going.. got home..JUST .. then after a couple of hours wen she had cooled i tried to restart and she did first turn but still sounded like crap, engine knocking noise and bad vibration, smoke from exhausts idled roughly...then stalled.left it since to get some opinions but im alrrady fearing the worst so any help is appreciated...