Rx8 lack of power
 

My 04 Rx8 have a problem now. It was happen from last month. The engine light is on and then it's lack of power. I can't acceleration over 60mph, and then I 've do some research and it said it's a limp mode for Rx8 it will turn on when something wrong with the engine then at that night i try to start again and it was running well, power was back, but engine light is still on. so I called my local mechanic to pick it up then 2 weeks later he gave me car back and said it's because CAT system was failure so he took the CAT converter off. one day later, I was driving to work and then the engine light is come up again, but i realized that because he took the CAT off and didnt put a straight pipe that why the light is come up.
but few minute later, the car going back to loss power again. then 2 weeks later he said he can't fix it he just reset the ECU and the light go off and power is back.now i got my car back, but i have no idea how to do if the lack of power still coming up again because now the engine light is just pop up again, and i wish it was just an error that show because there's no CAT and this is the code when I plug it in with the reader.....P0420 Catalyst Efficiency low bank and U0155 Lost comm with Instrumental Panel Cluster Control Module. could it be something about ECU problems? because at first day problem was come up because I unplugged the battery to clean the acid around, and i unplugged 2 of them not just one.

Loss of power could come from a bunch of issues. You ruled one of them out by taking off the cat. When your mechanic took off your cat , did he notice to see if the honeycomb filament was still inside the cat? If its still there , then you need to change your plugs , coils , spark plug wires and air filter.

If the honey comb was not in the cat , then it stuck in your exhaust and causing major restriction. I know this because this is what happened to my car. The cat guts broke apart and got wedege in the exhaust causing loss of power, high levels of gas fumes coming back into the car , and causing the car to die on my in my travels. Purchased a new cat back, problem solved .

Hope this helps or leads you in the right direction.

Take your car in for a compression test.
There's no point going any further unless you can find out that driving around with the ignition system in bad enough shape to kill the catalytic convertor somehow didn't manage to kill the engine too.

The problem is that catalytic convertors don't just die.
They are killed when the engine is run for a long period of time with the ignition system not properly firing the fuel mixture. This is caused by weak ignition coils, fouled spark plugs, and worn out ignition wires.

So, go get a compression test.
If the car passes the compression test, have the ignition system tested and replace what fails those tests. You are probably better off replacing everything all at once so you know where you stand, but some people prefer to only replace the known failed parts.

If the car doesn't pass the compression test, if your car is still within the 8 year 100k mile warranty period, you will get a replacement engine from a local Mazda Dealer if you live in the US or Canada. If you're outside of those bits either by mileage or country, its on you to pay for a rebuilt motor.

BC.

Compression has nothing to do with his symptoms. I had low compression before my exhaust got clogged and could rev alll day long to 9500 rpms. Low compression symptoms would be hard cold starts and even harder warm starts, ruff to severe idle,occasional very high rpm hesitation like in my case , the new redline for my ailing car was 8500 rpm, couldn't reach 9500 rpms any more.

When my car started to do this at 177k miles, i rebuilt my motor myself..

Also he has symptoms of a carbonized SSV valve. This also presents itself with no power above 4k rpm. If I was him I would rule out all the easy stuff or DIY before paying for another motor or having it rebuilt. And for good measure since you mentioned it, go ahead and get a compression test.

Obito, also clean your MAFS sensor, that is also known to throw symptoms of power loss above 4k rpm.

bad cat

plus ur ignition is bad, i bet u never changed them

get those fix and u will be good

as for the u0155 code make sure your tech did not mess up the wiring.

Just because he has more power above 4k rpms, doesn't mean he has all his power. There are plenty of people running around on RX-8's with low compression motors, not making all the power they are supposed to, that don't realize they are having an issue.

Yes, part of his symptoms sound like the SSV valve is stuck, but since he had a convertor failure already, you need to find out why the convertor failed. Since we know convertors are killed by faulty ignition systems, that's going to have to be looked at.

But, before we even start looking to replace the ignition system, it makes MORE SENSE to look at the compression, and find out if the engine is even worth putting all these new parts into.

What's the point of dumping hundreds of dollars into a new convertor, new coils, new plugs, and new wires only to find out his compression is low after all that?

He never mentioned how many miles are on his car, so it might not be worth it to him to pay for all of this stuff, and then have to turn around and pay for a replacement motor if he would have to pay for it out of pocket, if his pockets are empty.

All he's told us so far is that he has an '04, had his convertor removed (possibly open exhaust or with a midpipe now, can't quite tell), he has flashing CEL, and no power anymore because his ignition system has crapped out, yet he kept driving on it like this.

I'm not even going to try to do anything with the Lost Comm error.

So, start with compression.
Find out if its going to be out of pocket or covered under warranty, and then we can recommend stuff from that point on.

BC.

As a poster above said, pull your mass air flow sensor out and give it a good clean. Costs $10 and 10 minutes of your time. Had similar symptoms on my last car and the stealership wanted me to buy everything from 02 sensors to plugs, wires, . You never know, but no harm done right?

my mileages is over 130k now and i've meet my local rotary mechanic. he said it could be bad coils, so he took em out and yea most of them are burnt. now, im waiting for parts to be shipped to me, so then i can replace it, and i hope it could be fixed. ty for all answer :)

my rx8 is losing power but its not all the time. it only likes to crank when its cold aslo. ive been told everything from o2's to my apexes being blown I don't understand because im new to the whole rotary motor I was raised with old school small and big block dodges. when cold it drinks gas and smokes till warm. then the other day it started just randomly shutting off wile driving and will not crank unless you turn it over with the key. so I took it to the mazda dealershit and they said yepp your fucked cause your apexes are blown I don't understand how it is still cranking it has 143k and there telling me it should have blown up at 80k so I was hopping yall could help because idk if I should buy a motor or just wash my hands with the car and sell it?

The rotary engine is a 4 cycle engine just like a piston engine. It just spins instead of going up and down. Think of the seals as piston rings.

Wither you keep the car and repair it or sell it depends on you. A Mazda re-manufactured engine, replaced by the dealer, will run you about $5000. It takes about 8.5 hours to replace the engine. There are places around the country that rebuild/re-manufacture the engines. You may be able to save a few dollars using them, then getting someone to install the engine. If your close enough, the re-builder may also be able to replace it too.

First off, you should probably put your post in a thread in the correct section of the forum.

You should search out similar threads with identical issues, and see what solved or helped their issues.

Did you pay your Mazda dealership for a compression test?
If you did, did they give you the compression numbers?
If yes, post them. If no, call them and demand the numbers, and then post them.

You should have read our FAQ section before you bought your car, but it's not too late to read it, and learn what you have on your hands, and decide for yourself if you want to keep it, or toss it.

BC.

Im having some issues with all 3 solenoids right now and o2 sensor its saying that that curcuit low ik its a wire somewhere that has to be touching because i replace all of them and im still having the issue of not being able to rev past 4500 (revs slowly) but im trying to figure out where is the common ground for them

Hi guys,
My 04 rx8 standard goes into limp mode when cold,,P2107 and P2108 errors
I have changed 6 throttle bodies already as well as 3 accellerator pedals...still problem persists
Have replaced ABS, engine wiring harnass and ecu still the same

Any ideas would be appreciated.

Once car reaches normal operating temp, i can drive for miles etc without any problems

DTC P2107

DTC P2108

According to Mazda, those problems are caused by a bad PCM.

Engine light no exceleration
 

My 04 is doing th his but....if the engine light is on I cant accelerate it goes very slow and then slowly builds speed but not much like 30 miles per hr. Then if I take battery cables off and put back on the light goes off and car drives normal again for long periods of time then all of a sudden after driving and then stopping like at a store getting back in starting to leave and here comes t j.g e engine light on as gain and no power. Car has 93k last year changed 02 sensor also the abs and dsc lights keep coming on. I dont work on the car so I have no clue on these things took it once to have code read and guy told me I needed new computer but didn't give me the codes cuz he got codes as a favor to guy over at Auto zone cuz they kept getting linking error. Any ideas why I have power with no cel but then no power with cel??