**NEED HELP** 04 Mazda 3s 2.3L 4spd Auto

[Blu Mazda 6]

We bought this car and are trying to get it up to speed... We've noticed that when the car is stopped (ie redlight) the idle drops a little below the line under 1000RPMS and gets rough, if you put the car in park or neutral it idles back up to the line below 1000 and idles smooth.

When you turn on the car and put it in gear it does the same rough idle and feels like it sinks a little. When you put it in park or neutral it idles back to normal and raises a little as well, as if the pressure is being taken off of the drive train. As an experiment I pulled the E-brake and started the car and put it in gear and it sank the car but didn't idle rough, only when I pressed on the brake PEDAL did the idle seem to drop down.

does it not disengage all the way? we took it to a shop and they said it could be a motor mount, or that some FWD cars have a tiny shock absorber or mount between the engine and transmission that wears out over time, do our mazdas have that?

Some stats on the car:

2004 Mazda 3s 2.3L with a 4spd Auto, 118,000miles (rounded up)
Clean title, no known history of the car tho.

 

[tomk17]

I would start with the basics:
- is the air filter good
- are the spark plugs reasonably new
- run some Techron or Seafoam thru a tank of gas to help clean the injectors
- could clean the throttle body - not sure how mechanical you are but I can give you a quick "how to". Involves removing air cleaner box and that big fat rubber hose and blasting some Throttle Body cleaner in there.
The passenger side motor mount often breakes in these cars. My 04 with 63K miles just had it replaced at dealer just before I bought it for about $275

 

[Blu Mazda 6]

Heres the rest of the stats:

- Air filter is a K&N stock replacement filter just recharged
- Spark Plugs looked ok upon inspection
-- Have NOT ran Lucas Fuel System Cleaner through it yet in the trunk waiting to be used.
- Throttle body looked mostly clean, (SMALL dark rim around the inside [not the flap]

--- I did however pull a code off a week ago or so saying that the Throttle/ pedal position sensor received high input? any idea what that could mean? Advance said I'd need a new sensor (but never can tell if they're just trying to make money or know what they're talking about)

 

[_Chris]

It very well could be a worn out motor mount. These cars do not have the engine dampening strut on them. The most common mount to go bad is the rear lower mount. And in a auto when you place the car in gear it applies TQ to the engine. If you had the hood open on most any FWD auto car. If you place the car in gear and then into park/neutral you will see the engine shift back and forth. The rear mount is very easy to remove and replace in these cars. Just takes a 17mm and a 19mm. It takes more time to jack the car up then it does to take the mount out. You don't need to support the engine when you remove it ether.

 

[hat1018]

Have you tried to reset the ECU?

 

[05Mazda3sp23]

i would try and clean your MAF, seeing that you have did most of the basic checks... like said look at rear motor mount.. keep us up todate

 

[weatherdan822]

I have the same type of car with all the same symptoms, I assumed that this was normal functioning of the car

 

[Blu Mazda 6]

Ran some lucas fuel system treatment through the car and it still does the same rough idle, I'll have to jack up the car sometime this week to find out if the mount is bad. I REALLY REALLY hope this is not normal ops for this car. We replaced the battery so that SHOULD of reset the ECU right? if not I should be able plug in my OBD2 tool and reset that way right? Not to sound noobish but how do I clean the Mass Airflow I thought that was just a section of the intake hose? or is MAF something else?

 

[hat1018]

Yes, replacing the battery will reset the ECU.

 

[05Mazda3sp23]

Ran some lucas fuel system treatment through the car and it still does the same rough idle, I'll have to jack up the car sometime this week to find out if the mount is bad. I REALLY REALLY hope this is not normal ops for this car. We replaced the battery so that SHOULD of reset the ECU right? if not I should be able plug in my OBD2 tool and reset that way right? Not to sound noobish but how do I clean the Mass Airflow I thought that was just a section of the intake hose? or is MAF something else?

well if u have a cai or sri(cold air intake or short ram intake) or stock intake, its the black box on the intake tubing and there "http://www.mazdas247.com/forum/showthread.php?123668164-How-To-Clean-Your-MAF-Sensor&highlight=cleaning+air+flow+sensor" is a write up same basic idea hope that helps

 

[Blu Mazda 6]

I'll have to find some time this weekend or something to pull the MAF and give it a cleaning I doubt it's been done before. Its now became a lil bit worse, it seems to "shudder" once when it comes to a stop. I'm really hoping it's not a tranny problem. Does anyone know what could cause this? I know it's hard to diagnose without seeing it but I thank you guys for all your help.

We ran an autocheck on the car to find out a lil more about it, and we're the second owner of it the car had a lot of miles put on in a short amount of time, it was a military car, no reported wrecks, flood damage or anything else. Just wish it would of been as nicely taken care of as my 6 which was a military car as well and continues to be pampered haha. Will keep you guys updated.

 

[05Mazda3sp23]

maybe tranny flush... i just did mine at 110,000miles... its not a bad idea but it was like $80 some bucks for me... so look at it frist