Hey there,
I've scoured the forums for the last couple days trying to find answers for my problems but I can't seem to find a solid answer.

A little background info:
- 2006 gt great condition when bought at 53k kms back in Nov
- now has 60k kms
- had misfiring problems back in Jan, replaced all coils and plugs with BHR (ran amazing after!) but ran with misfires (code p0301) for about 2-3 weeks before the cel starting flashing and I fixed the problem
- has AEM CAI and racing beat exhaust newly installed, below problems began occurring after installation.

Now I'm starting to get rough starts in the morning, power loss (MAINLY uphill; feels like it's hiccuping constantly when I put the throttle on), and I've had the misfire code p0301 again, twice in about a week.

Yesterday though, I started the car in about 12 degree celcius weather and let it idle for about 20 secs before putting it into first. Unfortunately I think I must've let off the clutch too early because it hiccuped and almost stalled-- I saved it, but not before the dash lights quickly flashed on and off. When they turned off, the engine light stayed on then begun flashing. I hadn't done 10m yet so I threw it into neutral and rolled out of the way (as I was on the street). Left it there for a bit (~3 min) and the cel stopped blinking--went away completely.

I decided to continue driving but it felt fairly powerless. After the car warmed up I got on the hwy and when slowing down in 5th it made what I thought was the MIAC noise, twice. Not sure what to think though because it was much much louder and more grinding-sounding than what people are reporting, and it wasn't happening at high revs like people say (over 6k rpms). It also was only happening for 2-3 seconds at a time.

It doesn't seem like I'm having any problem starting up on a hot engine like many people with compression loss but I'm worried the other symptoms may be pointing towards that. It's just acting very strange and hiccuping a lot, misfire codes, etc.

Does anyone have a suggestion as to what I should be looking for or what could be wrong? O2 sensor? Clogged CAT? I'm hoping it's the CAT because I'm looking to get rid of it anyway. Any info is great, I'm just trying to catch this problem early!

 

missfires lead to clogged cat. clogged cat leads to wasted engine

 

I'd suggest looking at the cat and possibly into a compression test.

 

Lots of reasons for misfires, including some problems that are caused by misfires can themselves cause more misfires.

See my signature below this post for a relevant thread.

 

yeah see that's what I was thinking/hoping! that it's clogged from back when I ran with misfires and bad coils and plugs for 2-3 weeks.

question is, what's the best way to check? I hear driving it hot for a while at night and check if it's glowing when you stop? If it is the CAT how long do I have before it really starts to take a toll... it's my daily driver and parts take a while to arrive

with compression loss though wouldn't I feel it badly when the engine is hot and I try to start it?

 

can anyone else offer a possible problem? or give a reason as to why it would or wouldn't be the CAT? I've heard its possible for it to be the O2 sensors? Would I have ruined them by driving with misfires?

 

you are having misfires. you have to diagnose why. check the coils and plugs and wires first. also check the eshaft sensor is not fowled and then reset the memory for eshaft position with the 20 brake stomp procedure

 

Did this ever get solved? I'm having almost identical problems. I want to be ready for the DGRR but worried I won't fix it in time.

Posted From RX8Club.com Android App

 

Uhh... Sorta.
I ended up bullying my dealer into installing a new engine inder warranty (it's amazing what a girl can get done by strapping on some heels) despite him insisting that it wasn't the engine. Apparently i had very slightly low compression in the first rotor, but when they seafoamed it (some mazda zoom zoom cleaner) it was running strong... according to them.
Anyway, that was back in late August, it was fine for a bit, or at least somewhat better, however I'm still getting rough starts and misfirea (no codes though, it just doesn't feel 100%)
I've had several electrics mess up, (my daylight running module is out, airbag light flashes up on the dash to indicate some errors, and other random things) so I'm suspecting an issue with the ecu, which is also something the dealer mentioned may be the root. I do have an 07 though so really I shouldn't be having these issues..
Oh well

 

The strange thing with mine is that it actually starts better when warm, and idles fine, so I don't suspect the compression is the issue. However a new issue has come up... The sand in a blender noise from the glovebox. In peak torque range in 2nd and 3rd I'm hearing it on a regular basis. I've read it could be the heat or bad gas but neither of those apply. My gas mileagehas gone down considerably as wel, but that could also be because of my winter wheels and colder weather.

 

Mine had a few instances in the last couple weeks where it didnt want to start to well either(given.. i AM in alaska..) but it hasnt been an issue for the most part. Anyways, the car didnt start well, finally got it started and let it warm up thoroughly before leaving. When i got onto the highway i got on it to clear it out a little (smelled pretty saturated from poor starting and minor flooding) so when i got on it, it hit 7000 and it was like it hit a wall and cut power instantly and started throwing a flashing cel. I slowed down and killed it and started it by poppin the clutch and the light wasnt flashing anymore. After that whole thing, the car has NEVER ran better than it does now. Complete mystery to me lol. anyone else have something like this happen?

 

I would suggest you get your codes scanned.
Do you still have a catalytic converter?
Flashing CEL means misfires, misfires clog cats.
It could have been a chunk of cat strata clogging your exhaust suddenly blowing out.

 

My cat is gutted.. so its probably not that lol. It was feeling restrictive when i first bought the car at 57,000. Gutted it till I get my catless mid. thats kinda why im at a loss because everything points to the caty lol. and now my light is off, wont come back(which is weird) and runs amazing.. fuel economy is improved.. everything.. really strange. maybe i had some stuff from when i gutted it that i overlooked pass through..

 

Update: went for a hard but short drive today and checked under the car for a glowing cat after... Ohhhh yes. Bright red. A catless mid is the next move, it should make a difference. However, i doubt this will change that sand in the glovebox noise... Still at a loss for what it could be. I just want to be sure its not an indication of something worse.
Based on your experience it seems like grtting rid of the cat was a significant step in the right direction; I'm excited to see the results with mine!

 

Hi, I have not heard of the noise you're describing. Just a thought here, have you changed your cabin air filters?
Maybe they're full of debris.

 

I've considered that it may be something like that but wouldn't i only notice it if i had the air on? Or at least notice it more? :s
I did a bit more reading and it seems like some have said it's a sound that comes with a failed cat. Literally the substrate falling apart and making that noise in the cat when the engine is blowing lots of exhaust through (exactly at peak torque ranges).
I'm now hoping it'll go away when i install my mid; if not, I'll be back!
Thanks guys