RPM drop when air-con is turn one
 

RPM drop when air-con is turn one, car vibrates at idle. when pull to D vibrates get worse, can see the RPM drop a bit. any idea why? if its not mounting.

could it be the cat is block?

let me guess, you didn't do a Search, did you? :rolleyes:

The way around it is to rev the car to redline. The reason being that the a/c is disabled at that point. Works well for me.

It is normal for the engine rpm to drop when the A/C is activated. Do the RPM's come back up when you turn the A/C off ?
My A/C is always on ,so I don't notice the drop. If for some reason it has been off and
when I turn it on,, I feel the load of the compressor. And RPM drop.
It is normal for it to do this. Don't panic. If for some reason you think it is an issue ,take it to the dealer.

so does this mean the vibration is not due to A/C ?

did a search and couldn't find this

It's fairly normal for rpm's to drop a little when AC is on or you put a load on the motor. Does it vibrate only when AC is on. You gotta AT right? I seem to recall some bad motor mounts causing vibration on AT's.

It could be the engine or trans mounts. How many miles on the car?
They changed mine at 23,000 miles on our old RX-8 AT.
This was due to a noise/rattle coming from under the car.
They installed both engine mounts and a tranny mount. But I did not notice any strong vibrations or any unusual vibrations at idle for that matter.

Check the thread called "Flash, new flash" or something like that. Very good information in there. If there is nothing mechanically wrong, you may find this info useful. Sounds like the update works nicely for this problem, and gives some other benefits too.

The problem are the engine mounts , just changed them today and the vibration is gone, check them out there is a service bulletin for them.

Nice!

this is what i face i guess i hear rattle coming from the front under my car. must be it!

any idea where i can get the Racing mounting by RIGID
or get the original one from mazda? mine is PI car.

Get Mazda to replace the Engine Mount, they had some crappy material before and it will crack overtime.

after that, reflash your PCM to the newest one, if u'rs is a 04, it should be S, mine, a 05 looks like some F or something. 06 I dont know.

You're car should be fine as long as u do the above.

It's more than crappy materials, they were being destroyed by the engine heat. I think the newer ones have a heat shield.