I have an 04 Mazda 3 auto. When im at a stop light, while holding the brake. The car has a vibration. Intermintly the car will feel like it trembles for 1-2secs then goes back to normal, then comes back after a few secs. Is this normal? The dealer said it has something to do with either the compressor kicking in or the variable valve timing. Any truth in this?

I just hear about these cars breaking motor mounts. Its not constant but cycles on and off ever few secs (10-15) no cel lights are on, no codes

Thanks for any help.

 

I don't believe the 2004 had variable valve timing, so I rather doubt that's the issue. As for the compressor kicking in, that is a distinct possibility; if you want to test it, turn your fan control to "0" and see if the problem goes away.

The HVAC controls of my Mazda3 are the most aggravating issue I have with my car; it seems there's an idiot savant (more idiot than savant) in the dash that determines when to engage the A/C compressor (even when the vent controls are set to "Floor" and the A/C button is "Off"), and the only way I can be assured of the A/C not kicking in during the dead of winter is to set the blower to zero.

 

I did some research last night. From what I can understand it's just a characteristic of a 4banger. They all do it to some extent. It's amplified by the 3's engine mounts. It happens when the compressor kicks in putting more load on the engine and the engine not wanting to speed up the idle.

 

Well...

While 4-Cylinder engines are inherently less balanced than pretty much all other engine types commonly found in cars, they don't "all do it". To be sure the load of an A/C compressor on a 4-Cylinder (4-Stroke) engine at idle can exacerbate the natural imbalance and natural torque-reversal issues of this type of engine, the 4-Cylinder engine in our GTI feels just as smooth at idle with the A/C engaged as it does with the compressor off.

 

Will I was sitting in my truck to day (v6) I noticed the same type of vibration. Wasnt as noticeable but still there. I don't think it's anything to worry about

 

First of all, in '04 and possibly '05, the 2.0L did not have VVT, but the 2.3L did. I know from experience.
Second, yes, the RS upper mount has a tendency to leak in time as it is basically a fluid filled bag. The rubber cracks or is otherwise damaged and the fluid leaks out. The mount drops.
Third, if you have a tendency to keep the heater control on the footwell position (12 o'clock) or any further clockwise than that, the A/C compressor does cycle.
Fourth, cleaning the MAF and IAB sensors once in a while, or replacing the O2 sensors may help this problem also.
Fifth, if your car has over 70,000 miles, you might consider a new set of plugs... and the recommended (re: safest) brand are NGK. these cars seem very sensitive to plug manufacturer's and their specs/tolerances they are made under. Others have been known to have difficulties experimenting with other brands.

That's all I have for now. If you have further info to share, there may be more.....

 

In the case of my car, the idiot-savant in the dash has the A/C compressor cycling year-round, regardless of which vent setting I've selected; I cannot tell you how annoying that is.

As I said before, the only way I can keep the A/C compressor from cycling is to set the fan control to "0"; unfortunately when I do that and I'm running at anything less than freeway speeds, it can get pretty durn cold in the car.

 

I replaced the air filter, and its alot less noticable. I plan on doing the spark plugs here soon. (gotta save up some money first lol and i gotta wait till my friend to come back in town (hes got all my tools)). Im going to slowly do all the 100k maintenance (only can do alittle at a time...stupid not having any money thing lol) My car has 92,4xx miles on it at this moment.

Lol, i have to run my fan, i live in wisconsin it was 24 degrees this morning. Also if i turn off the ac button its alot better too. Sure my air isn't getting the humidity taken out but at this time of year there is no humidity.

 

Yeah, it gets plenty cold here in New Hampshire as well; it drives me crazy that the A/C compressor continues to cycle even when the OAT is down near 0°F (something which should never happen; most of my previous cars wouldn't allow the compressor to engage even if you selected MAX A/C when the OAT was below about 27°F).

 

I don't get it either. You'd think that since its so dry already the car wouldn't run the compressor. I know it runs it to take the humidity out of the air...what humidity? lol