Intermittent Power Loss, MIAC, and Oil in the Intake
 

Has been happening for a couple months now but now I'm just getting tired of it. It usually only happens when I drive on the highway for a bit. Sometimes its so bad I can barely get going from a stop. I scheduled an appointment at the dealership, over 60 miles away, and I'm just doing some research trying to if its going to be an 'easy' fix. I have read and it sounds like I could either have a bad cat, need to upgrade my ignition, or need a new motor. I'm a bit confused by the amount of oil in the intake. There is probably about 1/4-1/2 cup of oil in my intake. Does anyone know what this means? Great timing too, there is an autocross next week:banghead:

Most likely it's a clogged cat or bad coils as you suspect.
if it's a bad cat, that's fairly easy to diagnose. Jack the car up, loosen the bots connecting the cat to the exhaust manifold and take a peak inside. If chunks fall out, the kitty is dead.

Coils also are somewhat easy to check if you have a multimeter. If you do: http://www.finishlineperformance.com...16-07-1793.pdf
If those are the original coils save yourself the time and replace them. You can get good prices on them from Mazmart or onlinemazdaparts.com


MIAC: could be air in the heater core, some people had their coolant systems flushed and the problem went away.

Oil in the Intake: when you pour oil in, are you using a long funnel? if you aren't, the oil could be going down one of the breather hoses and into the intake box. That's a common issue but easily fixed.

MIAC: could be air in the heater core, some people had their coolant systems flushed and the problem went away.

Or, they have installed the restictor in the line( https://www.rx8club.com/showthread.p...ght=owner+miac start at about post 12 or so)

Oil in the Intake: when you pour oil in, are you using a long funnel? if you aren't, the oil could be going down one of the breather hoses and into the intake box. That's a common issue but easily fixed.

Or possibly it's being overfilled.....you'd be surprised how many dealers have been caught doing this.

Thanks for the quick reply guys! I'm just hanging out in my garage so I'll probably go ahead and jack up my car. I don't have a multi-meter but the $20 dollar investment would be a good idea I feel. Now all I need to do is wait for my air filter to dry so I can go to the parts store.

On a curious note, why does the heater core cause miac? It only happens at certain rpm's and only periodically. It also causes a loss in power it seems. After my highway trips back home it can take about 5-10 seconds of cranking before my car will start, and this is why I think a faulty motor might be in hand. I'll get back to you after I jack my car up.

hot start issues can be an indication of low compression but NOT always. Surprisingly, I found this out with a member's car two weeks ago.
He is fairly consistant hot start issues, we compression tested his car but he's still above the minnimum psi levels. Go figure. :dunno: (coils / cat are not an issue on his car)

the power loss might not be linked to the MIAC, could just both be happening at high rpm's.

quick warning: let that cat cool off for quite some time before unbolting it and don't have your face directly underneath it. unburnt fuel could be in there. you get the picture...

haha Thanks for the heads up. It has been parked for quite a few hours now so I didn't even think about it. I would have noticed the warmth when I was trying to unbolt it though

Just a heads up --- if your cat's honeycombs look good it still may be melting in the lower second section after the o2 sensor which you can't see. I just dealt with this a few days ago. Car was lacking high rpm power and making an interesting metallic sound. Pulled the cat and it looked good, but a friend gave me a midpipe so I threw it on and booyah! Problem solved.

^yeah............I read that thread. Interesting.
If you completely unbolt the CAT and take it out and shake it a bit, I'd think you'd get a good answer.
If it's plugging up and you run the car pretty hard, when you get home and take a look it will be glowing!

Might just have to go run my car hard for a few then haha.

I tried getting it disconnected but the bolts wouldn't loosen. I didn't have any wd-40 but I put some oil on it hoping it would penetrate. It helped, but not enough. I borrowed a buddies compressor and gun but that wouldn't fit on the bolts... So I guess I'll have to spend the $100 so mazda can figure it out...

Hey Mazurfer, I was expecting to hear rattling when I took the cat off and nothing. As for glowing red, I tried doing that too but never seen anything. I forgot to mention that in my post.

Stingray, just hose those nuts with PB Blaster and let it sit about 30 min. Get a 14mm and longest bar you can get. Mine came off pretty quick after the PB Blaster. I've read about the tests Mazda does for the cat and theres a possibilty of passing due to the test doesn't take place at high rpm or whatever, if thats where your power loss is. This is why I didn't take mine in. Would be a quick waste of $100.

I'll keep you guys posted. I'm going to take it and run it hard after my filter dries. If it's not glowing red I'll be sure to tell ya. As far as tomorrow, taking it to Mazda, hopefully(haha) I will have to get a new engine so I don't have to pay for anything.

Well the dealer saw numerous misfires so they stopped there. What is a good place to get coils online and what is the pricing? They are quoting me at 61.99/coil which I don't think is too bad.

Get the bhr kit or fabricate your own. Pays itself off in the long run and the coils are twice as powerful, plus from what I've read if you have the AP you can change the dwell times to extract a little power. totally worth the money IMO.

stingray: if you want OEM coils, talk to the guys at Mazmart or check out www.onlinemazdaparts.com The last time I bought coils they were about $30 each. Installation is a BREEZE so don't worry about that.

if you want coils that'll last you a LOT longer, look into the BHR system.

I just replaced them with stock ones, that way no one will give me grief when autocrossing. Also, driving home, my car stalled at the first red light I came to. So my coils might have been bad, I had over 1000 misfires, but I still think I have bad compression. They also did the cleaner.

Just installed the coils and took it for a spin. I recreated highway driving and I also took it on the turnpike. When I was coming back into town I didn't notice a significant power loss but I noticed a low idle at the first stop light. Come the second stoplight it idled down and died. I tried restarting it but it wouldn't start. I kept cranking(20-30 seconds) and it finally started up. I'm going to call Mazda again tomorrow and they will probably want me to schedule another appointment. :mad:

Why couldn't they have just checked the compression in the first place. Also, I looked at my coils and I didn't really notice any 'bubbling' effects that I have read that shows bad coils.

Good luck! Sounds like new engine time!

1.) White spots and bubbling are really NOT confirmed indications of bad coils. Only way to know for sure is to test them.
2.) If they(or you) pulled the battery when doing the coils, then the car needs to re-learn the fuel trims and this could result in stalling out for a few drive cycles. Usually clears up pretty fast.
3.) Worried about your warm re-start though. :(
This could be a sign of compression as you know. Hopefully now that you have coils and no CEL they will run the compression test.

Good luck!

I probably had driven 10-12 miles before it stalled. Would this be enough time to relearn the curves? I think it would be because later last night I was driving and it would give a rough idle at some points but wouldn't idle below 500 rpm.

Would it void my warranty if I told them that I occasionally race auto crosses? I haven't told them but I'm just curious.

I'd say a few hundred miles, when I reset mine i took about 3 drive cycles and a total of 200 miles or so.

^............that unusually long IMHO. Mine usually takes no more than three drive cycles at the most, and those can be a short as you want to make them. I usually just tool around the neighborhood a few times.

^ I'm just guessing mazurfer. I took a long highway drive so I'm sure the mileage is incorrect but it was after the third drive cycle that everything smoothed out.

So it has been about a week and a half now. Really hadn't done any highway driving until today. After about 70 miles I pull into my parents driveway and it dies. Takes about 10 seconds to restart.... Ya, I know what everyone is thinking now.

So my mom and I go out to eat lunch and hardly any power out all, it is either misfiring or something bad. So I call Mazda (yes, they are open on Saturday, How awesome is that?) and scheduled an appointment. The service manager is a good guy and i have been dealing with him for a couple years now. He said it sounded like I needed a new engine but they have to run some tests and jump through loops for Mazda... Looks like I'm joining the club. I'll let you guys know Tuesday.

Good info thanks Jedi