[jspec28]

Hey all, been looking through the forums for a few years now, and have found very useful information, thank you all for that.

I have not experienced many problems with my '04 V6, other than the norms, clutch, battery, etc. I just recently started to hear my CV joints clicking, think it's passenger side.

Anyway, two days ago I was taking the highway on ramp, and heard a terrible grinding noise. It was almost like something was caught in a fan blade. The noise subsided when I took the car out of gear, and came back when under engine load. At first I thought it was the CV joint breaking, but then I noticed the CEL flashing.

I got off the highway, and took the back roads home, about 5 miles. The noise started to go away, but I now had a solid CEL. I got home, shut the car off, and checked the oil, it was right at the bottom of the OK mark. I added about a quart, and the noise went almost completely away. I drove the car around the block a few times, and didn't really hear any catastrophic noises, just noticed some bucking around 3k RPM.

The next day I started the car again, and it sounded almost like a diesel, the valve train is what it seemed to be. Checked oil again, and added about 1.5 quarts to get it all the way up. The noise completely went away, and the car sounded normal. I drove it about 20 miles to a mechanic and dropped it off last night.

The mechanic called me this morning and said the CEL was misfire on Cyl #1.

As a side note, the car has been using ALOT of oil lately it seems. I do know about the PCV, and asked the mechanic to look into that.

My question is, what was the noise I heard, and do you think if I drove with a misfire for 20 or 30 miles would it ruin the cats right away?

Any help or suggestions would be appreciated, thanks!

 

[flipper66]

the Grinding noise is due to lack of oil......

Driving with a miss isn't great, but no telling what it did to your cats w/o removing them.

 

[aztrojans12]

I hope the best for you, but I really hope it isn't precat failure. Sounds like you are losing ALOT of oil quickly. Doesn't sound good.

 

[jspec28]

Mechanic attributed problem to a bad coil. He checked compression, injectors, PCV, and vacuum system, all OK. Swapped cyl #1 coil to cyl #4, and CEL came up with misfire code again for that one. I hadn't changed the oil in quite a long time, and it was very dirty. All together with a new CV joint and oil change $500.

 

[beard0350]

Sweet. Problem solved then right? New coil?
Oil change is real easy too. just do it yourself. Next time between 4K-5K when the wife and/or kid are screamin, get it done, it's a great excuse to get away. Hell, bring a portable tv with you and get under there even if your not doin it, and when the wife bitches tell her to put the comments and complaints in the suggestion box over the trash can, and when your done doing important preventive maintenance (after the game) you will get back to her.

 

[flipper66]

Damn..... 500s thats crazy.

1 coil=50 bucks
1 new CV= 169 installed at local auto shops
1 oil change= I do it myself, but 60 or so bucks is about all I could imagine.

Some that is diagnosis, but damn.

there is no proven test to check if you have a bad CAT other than removing the bastards, but hopefully all is good.

PS damn, I just tell the wife I'm going out to the garage and she follows behind me and helps me fill things ups or works on her car.

 

[archeng59]

I have an '03 Mazda 6. 3.0L. CEL came on while driving on the highway. Mechanic said misfire on cyl 3, which is on the firewall side of the engine. He had to remove the intake manifold to replace all three plugs and coils. $570. Car runs pretty good now.

Before that occurred, I started noticing alot of soot on the exhaust pipes. Not burning all the fuel just because cyl 3 was misfiring for awhile? Could the PCV be part of the soot problem?

 

[jspec28]

Ya, $500 is kind of a lot, especially because I'm an avid DIY'er. I changed all of the plugs during the summer, which wasn't too bad. But it's really cold around here now, and my garage is full of crap. The brand new treadmill the wife bought is in there, which, mind you, has only been used a few times :-/ I wasn't really motivated to change my oil or swap a CV joint in my driveway.

Car runs great now, but I would recommend that anyone with a misfire should start by changing the plugs, and the coil on the bad cylinder. It's not that hard to remove the intake manifold. There's a great write up here: http://forum.mazda6club.com/3-0l-v6/176509-how-change-spark-plugs.html.

If you have a CEL flashing in your face, it's most likely a misfire, if you notice bucking or hesitation and have a solid CEL it's probably a misfire. I think Autozone and similar places will hook up a codescanner for free. That way you can tell which Cyl is bad. If you do it yourself you'll save a lot of money!

 

[flipper66]

Bucking and hessiatate could easily be a Vac leak.

specificly that hose attached to the PCV loves to crack.

Yes most autoparts stores can pull the code for free..... I keep my code reader in my back seat. You can also purchase a bluetooth OBD2 code reader and use your phone as a code scanner.

 

[roxyboarder41991]

i would make sure to keep up with the oil changes, i have a 2004 v6 manual and once you hit about 4,000 miles you can feel the difference in the performance, but i also need to replace my 2 front 2 sensors, so that could be contributing to the performance.

i got a P0171 and P0174 code, thats lean bank 1 and bank 2, does anyone know where those are located? and which is rear and front. i bought replacement sensors, but not sure which goes where.

 

[Speed135]

To Flipper66-Good tip on PCV hose cracking, would be cause of lean codes people are getting.