Rough idle issue

[cx9 2008]

I have a frustrating rough idle in my 2008 CX-9. I have almost changed everything and still nothing changed i changed coils, plugs, injectors, fuel rail, wiring harness, Ecm, fuel filters, intake manifold, brake booster, throttle body, done smoke test, both upper o2 sensors, deleted cats, alternator, maf sensor, cam sensors, crank sensor, knock sensors, coolant temp sensor, oil pressure sensor, fuel pressure regulator, rebuilt the whole engine with factory parts.

Can any body help me because im almost gonna give up but not after everything i changed, and by the way no codes show up!

 

[Silly Wabbit]

Not familiar with gen 1, but I think there's an idle relearn procedure

 

[GrampaSlade]

Proper diagnostic tools are a lot cheaper than a parts cannon. All those parts have to work together perfectly along with the computer.

 

[Lazy2.5]

deleted the cats?

and you think this is supposed to help?

 

[cx9 2008]

deleted the cats?

and you think this is supposed to help?

I've already deleted cats on other customers cars same as mine (for the same reason) with no side effects. And i deleted mine because they were clogged i only removed the upper part of the converter so it passes inspection.

 

[cx9 2008]

Proper diagnostic tools are a lot cheaper than a parts cannon. All those parts have to work together perfectly along with the computer.

I have all expensive tools and equipment. And sent the car to other shops that couldn't figure out the problem and all gave up, that's why its soo frustrating. I just had to shoot the parts cannon.

 

[cx9 2008]

Not familiar with gen 1, but I think there's an idle relearn procedure

There is, and i did it with with no difference at all.

 

[N7turbo]

It's possible that a Mazda tuner could look at a data log and see the problem pretty quickly. It will be fuel, air, or spark timing (or insufficient spark from plugs) most likely.

 

[Favre95]

I’d assume there is an IAC on this vehicle. May be worth checking into.

 

[cx9 2008]

It's possible that a Mazda tuner could look at a data log and see the problem pretty quickly. It will be fuel, air, or spark timing (or insufficient spark from plugs) most likely.

It's possible that a Mazda tuner could look at a data log and see the problem pretty quickly. It will be fuel, air, or spark timing (or insufficient spark from plugs) most likely.

Great idea, but why would the problem be one of those when i changed all of the realated parts?

 

[cx9 2008]

I’d assume there is an IAC on this vehicle. May be worth checking into.

I wish, but there is no IAC on this vehicle.

 

[GrampaSlade]

I have all expensive tools and equipment. And sent the car to other shops that couldn't figure out the problem and all gave up, that's why its soo frustrating. I just had to shoot the parts cannon.

So, all the data from the scan tool says that everything is working within acceptable parameters. The removal of the cats hasn't affected fuel trim levels. The cams and injectors are opening at the proper time? No vacuum leaks? Fuel pressure is nominal. What about motor mounts?

 

[cx9 2008]

So, all the data from the scan tool says that everything is working within acceptable parameters. The removal of the cats hasn't affected fuel trim levels. The cams and injectors are opening at the proper time? No vacuum leaks? Fuel pressure is nominal. What about motor mounts?

Im sure its a missfire because the car bucks at idle and the exhaust has a sputter with the engine shaking it also sounds off.
The things i want to do is check compression although i did but i want to reassure, check fuel pressure at idle.

 

[N7turbo]

Could take some logs with MazdaEdit, though getting started with it isn't free.