Ok, I looked on here but didn't find anything. When I'm really gettin on it hard, I reach about 6500rpm and the car stumbles and then pics up again. Does the same thing when I shift. Like I said, this is all when I'm really getting on it hard, otherwise, it runs smooth. Any ideas, or is it just a drop off in the power band??? Thanks for any inputs on this.

 

I am experiencing the same problem but in my case, it happens at 5K; a brief hesitation, then the engine continues revving higher. Yesterday, while running it out between 6-7K, I heard a rattling noise that seemed to be coming from underneath the hood. Today, when revving past 5K, the "check engine" light started flashing, then went off. I have been babying it ever since and will be taking it into the dealer Thursday.

 

Same problem here, most likely bad cat.

 

I haven't heard any unusual noises. But it just doesn't have a smooth, rapid acceleration. If I turn the traction control off (hold the button for 7 sec) it seems to help a little, but it could be my imagination too. Another new development happened the other day. I started it up, let it warm up and took off down the road. Just a real gradual, smooth accelleration to 6k, and it wouldn't turn any more rpm. I backed out of it and hit it again and it was fine. This has only happened twice.

 

Yeah check your cat. Mine was half broken up inside.

 

Might be the intake manifold. After many months of engine stumbling and CEL's Mazda recommended replacing the intake manifold. The manifold in the 6MT's has two different vacuum powered ports that open at higher rpms. They said mine must be sticking. I about passed out when they told me the cost to replace is $3K. Engine has to come out to do it. Thankfully after pushing them a bit, Mazda stepped up and replaced under warranty because I'd been fighting this problem for 6 months and had gone out of warranty during this time.

 

I just took my car in for the same problem this morning. Mine was the secondary intake valve? Something like that. And yeah, they'll have to take out my engine to replace that part!

I stopped driving my car in the mean time. They gave me a Mazda 3 for now.

Is there anything I should watch out for after they put my engine back in?

 

Lets see

it might be as simple as a bad cat, but if its a bad cat, your car should have a problem revving

If the choke happens everytime at around 6.2K~6.4K , and after the *choke* the car seems fine up to the redline, your SSV might have a problem, oh its part of the intake mainfold.

check and see what the CEL is.

If it is the SSV, dump a bottle of Fuel injector cleaner, I got the Prestone one, Rev the **** out of your car especially between the 6-7K rpm. Stay in 2nd gear, go on some interstate highway, keep it at least 6K, go up to 7-8, back down, go up, back down .... Thats how I got *rid* of my problem, been couple thousand miles already no more CEL. Car is running even stronger than before.

I think this is a problem that Mazda should look into, dont even need to replace any engine, 1 tank of gas with the *cleaner*. problems resolved. I think 7-8 bucks is much cheaper than replacing engine + labor.

 

If the Prestone worked I wonder if the BG44K would be the same or better(?). Early stage cat problems could mimic the stuck SSV problem and for the same general reason, impaired airflow. nycgps may be on to something just the same.....