I have a 2004 AT with 95k miles on it. Was having problems with tranny a while back and had it replaced with a rebuilt one. Trans problems are gone, but around 6500 rpm, it almost always feels like it won't open up fully and is clogged somewhere, usually stays around 6500 and makes loud whizzing noise and the car, when sitting still in drive, rattles and shakes like hell at random intervals. Brought the car in again to the place where i bought it (Nissan dealership), they said nothing was wrong and sent it to mazda to have it checked out. The guy at mazda said i need a new ECU and there's only one in the state and it's about $1500...i call bullshit...anyone confirm/deny this claim? He also said my motor mounts might need replacing, and that i needed a new catalytic converter because mine was clogged, which he said would be about $1500 with labor...also calling bullshit, thinking of going catless with a midpipe for the price. He did mention something about a valve being stuck somewhere though, which sounds like the source of the original problem that i was concerned with. If you guys could offer any helpful info on this case, i would greatly appreciate it...i just feel for some reason like i'm about to be screwed out of some money unnecessarily.

Thanks,
Regan

 

Cat issue - common - personally i would take a look at the BHR kit with the davesport cat, it will cost you about half the price of a new cat + labor

Valve stuck - ??? - not sure what valve they are talking about here...

Motor mounts - somewhat common - some people have reported issues on older models (like yours) with motor mounts. There is a DIY on the forums on how to go about replacing them yourself

ECU - rare (i believe) - haven't seen too many threads here on ECU issues, but you may want to do a search for good measure.

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You may also want to look at your coils and plugs, because if you replace your cat and you have bad coils, your just going to end up being in the same boat.

Many of the issues that you mentioned can be done DIY with parts that cost far less than dealership prices

Edit:

If you want to get some of your power back without paying for anything, i suggest removing your cat, and just blowing out the internals. Our cat's have 2 walls, generally the issue is that the first wall breaks apart and jams up on the second wall. Take a hammer with a dowel and break through the second wall. Granted you will get a CEL and fail emissions, but at least your car wont be choking until you get a new cat.

 

Do you get any CELs?

If motor mounts go bad then you have lots of vibration and unstable idle. If cat is clogged you lose power and you have issues with acceleration. I believe the vale they are taking about is the SSV one. It gets stacked due to carbon build up.

First I would check the cat to see if it is clogged. One way to do it is take the car for a hard run and then see underneath it. If the cat is clogged it should glow red. Motor mounts can be checked by any mechanic. The one that usually goes bad is on your left side (where the exhaust pipe is).

 

How about the Turbo XS Midpipe/Catpipe? found one for relatively cheap online.
I just got the quote from the mazda place...wowwza.
Diagnostic - $85
ECU - "Faulty" - N3ZC-18-881R (couldn't find a replacement with that number on the web) - $557.21
Clean and Lube Intake Valves - "Sticking" - $95.00
"Intake Service" - $105.00
Cat Converter, Nuts, Gasket, Labor - "Not Working Properly" - $1381.81
Labeled Under "Clyinders Misfiring":
4 Spark Plugs and Labor - $289.82
Air Filter - $28.76
Plug wires - $94.79
4 Injector Coils - $255.56
cabin air filter - $36.13

Left and right motor mounts with labor - "weak" - $501.08

Total: $4121.99

So, if i can't find another ECU with that exact number, regardless of whether or not it came off of a 2004 Automatic RX-8, then am i forced to buy a brand new one from them?

Will going catless or with a catpipe cause any problems with my engine or ECU?

Any alternatives to pricey dealership spark plugs/injector coils?

 

cat is bad - i can change it for u for 950 bux haaha.

valve stuck - most likely ssv. which could be replace for coouple hundred for an updaated part

ecu is pure bulllshit

engine mount - at 90 k miles. yes its bad. assume u never change them b4, another 300 something

 

How about the Turbo XS Midpipe/Catpipe? found one for relatively cheap online.
I just got the quote from the mazda place...wowwza.
Diagnostic - $85
ECU - "Faulty" - N3ZC-18-881R (couldn't find a replacement with that number on the web) - $557.21
Clean and Lube Intake Valves - "Sticking" - $95.00
"Intake Service" - $105.00
Cat Converter, Nuts, Gasket, Labor - "Not Working Properly" - $1381.81
Labeled Under "Clyinders Misfiring":
4 Spark Plugs and Labor - $289.82
Air Filter - $28.76
Plug wires - $94.79
4 Injector Coils - $255.56
cabin air filter - $36.13

Left and right motor mounts with labor - "weak" - $501.08

Total: $4121.99

So, if i can't find another ECU with that exact number, regardless of whether or not it came off of a 2004 Automatic RX-8, then am i forced to buy a brand new one from them?

Will going catless or with a catpipe cause any problems with my engine or ECU?

Any alternatives to pricey dealership spark plugs/injector coils?

Quote from dealership attached

 

if u live near nyc. drop ur car off for a day and i will replace all of them for u except ecu. which i highly dobut its broken..

 

notice how the dealer wrote "1 only left in country" by the ECU number...hard to believe but maybe i'm just a little paranoid

 

Start by replacing the cat with a working one or getting rid of it. See if everything clears up.

Get back to us after that. It honestly just sounds like your car needs a new cat and a tune-up and it'll be running like a champ.

 

alrighty will do, just ordered motor mounts and zoom engine cleaner for my ssv valve if needed. Working with a mechanic i know who used to fix suped up rx-7's. I will either knock the insides out of the cat or replace it with the Allflow cat, the fake one haha. I'll get back to you as soon as i know more, thank you for the help and advice.

 

Nah, our engines actually prefer a less restrictive exhaust system.

 

Good for you calling the dealer BS. Good advice so far. Please don't throw money at it to solve the problems.

The SSV itself may or may not be the issue since the CELs are based on the solenoid or the impact switch but can also involve the actuator or the vacuum system. Jon316G has posted a lot of info for troubleshooting these issues. You may get away with anywhere from just some labor to maybe an SSV assembly and labor on the high end.

Try to borrow a mid pipe to see if it makes a big difference before dropping money on parts.

Purchase plugs, wires and coils for ~$300 and DIY

Motor mounts may be outside DIY skills and equipment but you can still buy parts online and find a more reasonable install price

Intake service? WTF? Clean the MAF? Clean the throttle body? Very easy DIY