My 2003 mazda 6 is having some serious problems that no one around me can tell me whats actually wrong with it. The car is choking. All the sound is coming from the engine the exhaust pupes have air coming through them but theres no noise. We discovered that the cats were hollowed out but this was done years ago by the original owner. The o2 sensor has a spacer on it so I get false readings. Everyone keeps saying its the cats that need to be replaced but if this was the case wouldnt this have been a problem a long time ago? The fuel pressure is at spec also. The mazda dealership near me told me that the plugs and coils could be the problem too and fixing that would run me over a grand. They thought that bc of the code reading misfire PO300 . But my mehanic had put some "delete" on the car and he said thats why that code showed up. By the way no codes came up when this initially happened. i seriously need some help. I start school in a week and need my car to run. Any ideas?

 

Mileage?
Your car is old.
Usually the reason why cats are gutted is because it burns oil and or had misfires which melted the cats. It is also possible that some cat bits are stuck in the egr system. A compression test may be needed. Also please change the PCV valve and the hose attached to it as Mazda never changes it! Clean the MAF, EGR, and throttle body. Install new throttle body gasket. Check your accordian flexible intake hose for cracks, leaks.
The mazda ignition coils suck and are expensive. If you use MSD or Accel coils, you'll need to re-use your old Mazda boots and use NGK iridium plugs: NGK iridium # TR5IX, # 7397, .6mm tip.
Leaving for dinner now, good luck.

 

The cats were already hollwed out by the original owner and the o2 sensor is a dummy they put a spacer on it but the car only had 170000 on the car the engine itself only had around 47000. Im gun a work on cleaning the maf sensor tmrw but the air intake is aftermarket and the sensor is down by the inner fender so its gunna take some work getting too.

 

I Know, I told you why they more than likely hollowed them out

Hopefully the engine is good. I wonder if the 47,000 includes previous miles from the car he took it off! I don't know where you bought this from, but obviously he is untrustworthy. Also selling a car without cats/gutting cats is unlawful. READ: https://www.mazdaforum.com/forum/gen...effects-30404/ and http://publicaccess.supportportal.co...-Is-that-legal
You really need to clean/change that air filter. The air filter is in a bad spot as water can easily get on it when you drive thru water. The water and dirt gets splashed forward right on filter. This will happen when you drive thru the dips on every main road. You need a water shield.

 

I cleaned the maf and throttle body. No change. The motor had about 43000 on it when the guy I bought it off put it in he put around 2k in and me the same. The air intake hose had a small crack but it had already been taped over. The air filter was clean. Im gunna have the codes cleared and see what pops back up. Try to have some one with a data scanner check what codes are being thrown. The car was low on oil too seems to have a minor leak but nothing major for an old car. My mechanic wanted to take out all the hollowed cats out and o2 sensors and put all new ones in. I already bought two converters so there would be two more id have to get plus sensors. This car is just one big headache.

 

You could get the guy who sold you the car to pay for new cats, O2 sensors and/or take him to court for selling an unlawful vehicle (without proper cats).
as per my previous post.
The hollowed out cats could cause momentary hesitation/miss as the chamber may not be a smooth transition as per my previous post: Gutting cats thread.

 

Should I try and put on the 2 cats that I already bought ans see if that fixes anything. My mechanic is worried that the car will just burn them out thats why he wants to replace everything.

 

Depends if it burns oil and/or spark doesn't ignite.
Without spark the fuel will enter the catalytic and burn there, eventually melting the cat.
Do a compression test and visually check the plugs, check for actual spark.
That car has enough miles on it to change at least the spark plugs.

Please change the PCV valve as well. Mazda never changes it. A faulty valve could lead to burning oil. The earlier ones also have issues with the hose that PCV attaches to, so get that new as well.



https://www.mazdaforum.com/forum/mem...se-up-2227.jpg

 

But because the motor is a donor at less that 50k miles shouldnt the plugs be fine?

 

They should be ok for a while but it's best to do a compression test anyway before doing all that work. Plus doing them a little early is a good thing. To do a compression test they have to remove the plugs, so if compression ok, put new ones in. This way he can also inspect the plugs as per chart from post by tanprotege from: https://www.mazdaforum.com/forum/maz...ege-5-a-34072/ and inspect the coils.