Quick question about engine noise...
 

Hey all, new on here and only had my 2004 8 AT since October. I had a misfire a couple of months ago and got the spark plugs and coils replaced. Drove like a dream...until now, some two months later. Accelerating in 2nd causes a horrid rattling nastiness from the depths of hell, almost similar to the sound I heard when I believe the misfire occurred. Im very new to this if I'm gonna put some money into this, I want it to run like the day whoever took it off the car lot. Any ideas? Thanks for your help!

No flashing CEL's, right?

Obviously, you'll want to check that nothing has become disconnected or is loose in the ignition wiring - like a loose or broken plug wire. Pull the sparkplugs and see if they are all a consistent colour.

You should also check the engine mounts. There are many threads, and here is a TSB from Mazda


g.luck.

Engine mounts sounds like a good way to go.

CEL is a come and go thing, never flashes though like with hard accelerating after the misfire. It comes on for a day or two, then its gone for a week. I'll pull the plugs later tonight. Thanks for the TSB.

I hope your using premium gas.

Obviously, you'll want to pull the OBDII codes.

Some auto parts stores will read your codes for free (tell them it is a CanBus system).

There's a table converting the numeric codes to component descriptions in words: here

What RPM ranges do you here the noise? Full throttle? How is the idle?

Did it sound like a big coffee can with two marbles in it getting shaken hard? A hard metal on metal hammering.

Yup, straight up premium gas for me. The people I bought it from are gonna pull the code for me whenever I can get over to them. But the big coffee can with marbles is a perfect description of what im hearing. The idle at times can be rough, but when I hear it, I'd say im hitting 3500 rpms. Thanks for all the input and possible redundancy regarding my post!

It's very bad on the engine! I hope it's not damaged. You might have carbon build up and need a cleaning. Here is the "TSB" that shows one way to clean it. You might do the Throttle body bypass that takes a minute it has helped some.

http://www.finishlineperformance.com...4-08-1924g.pdf

Update: I pulled the codes and got this: P0456 EVAP system leak detected (very small leak) ON 2 EVAP system. Two actual codes, but they were both the same.

Here is the "TSB" on that code.....let us know how it goes...

http://www.finishlineperformance.com...26-07-1800.pdf

Hey guys, sorry about the relapse. Busy as hell with school for the past weeks. I have some updates. I need a new water pump and EVAP pump. Now I would do these myself, but I am no mechanic. I don't want to take it to the dealership in town cause I do not want a stock water pump. Any ideas who makes high quality water pump application?

As for the EVAP pump, I haven't a clue about this one, I just know what it does. Now, the filler cap I think I can manage, heh heh.

Anyhow, thanks again for the help.

For P0456, just replace your cap and see how it goes.

Why u need a new water pump ? is your old one leaking ?