Worst Things for Your Engine
 

Car MD has a top 10, i disagree with last 2 and changed them, as the new ones are very important for Mazda's, as well as adding a couple.
Some of you may disagree, but this is preventative maintenance. Why wait til something fails. If you drive to far with a failure, it could cost you a whack of money, so plan for it!

1. Putting off recommended / scheduled maintenance like spark plugs, brake servicing

2. Ignoring the “check engine” light

3. Not changing the oil, or not having it changed on time

4. Not checking tire pressure

5. Neglecting coolant, brake, transmission, power steering fluid services

6. Continuing to drive when the vehicle is overheating

7. Not changing fuel and air filters

8. Having unqualified shops service your vehicle

9. Not Changing your PCV Valve

10. Not cleaning your throttle body

11. Driving too far with a blinking Check Engine Light (Misfire)

12. Not putting in fuel sytem cleaner 1-2 times a year

13. Driving around with less than 1/4 tank of fuel. Over time this is what leads to fuel pump failure. The less fuel in the tank, the harder it is to pick up. This could lead to lean fuel conditions as fuel pressure is not there. FOR MORE INFO about this, see MazdaTirols Post # 5 (this is post #1).

14. Not letting your car warm up enough before stepping on the accelerator pedal too far. This is especially important for Turbo cars. And proper cool down period after giving it hell.

The best example of the snowball effect of missed car repairs is the air filter. It costs about 20 bucks to replace, but if left alone, a dirty filter can bust oxygen (02) sensors in cars, which cost as much as $250 to replace. And when the sensor fails, you'll first see your gas mileage plunge, then possibly wind up with a $1,000 bill to replace your catalytic converter.:eek:

The same as above occurs with misfires. With misfires, you are sending raw fuel in to the exhaust which ignites by the pre-catalytic converter causes temps to soar and could lead to melt down of the catalytic converter. :eek:

Not changing the PCV valve could lead to damaged pre-cat as well. A faulty PCV valve could send extra amounts of oil back in to engine causing carbon deposits and clogging of the pre-catalytic converter.:eek: Unfortunately, checking or changing the PCV valve is not on Mazda's service schedule for most Mazdas (see pic in attachments: N/A means Not Applicable --- really, who are you kidding Mazda) and i would recommend it changed every 2 years after the first 3-4 years.

Another item that should not be overlooked is the EGR valve. When stuck open it will send excess carbon amounts as well.

Changing the automatic transmission is another pet peeve of mine and is not on Mazda Service Schedule. (see pic in attachments: N/A means Not Applicable --- really, who are you kidding Mazda).
This should be done every 30,000 miles especially if a flush is involved.
I would also strongly suggest an external tranny cooler.
Some good articles: How often should the automatic transmission fluid... — Yahoo! Autos
Flush it or Forget it |*MotorWeek
Transmission Talk |*MotorWeek

So is there a quick fix or is it a complete new fuel pump?

Is it only the V6 that has trouble with the PCV?

NO. Read this post # 6: https://www.mazdaforum.com/forum/maz...-6-2-3l-30821/ :p
I know you have the 4 cylinder! Thanks for asking.

I remember in the older days, PCV valves were changed quite frequently like 1-2 times a year. Due to car manufacturers wanting to promote less maintenance, this has been omitted!

Pic below shows it on 4 cylinder below the yellow clip. Quote from someone: I had the dealer replace the PCV valve, it cost me $410. Number 13-890 in the bottom left, part number L325-13-890A, good for 04-08 model year 6i's, while ONLY the 03 6i uses part number L305-13-890. The cost from the dealer should be roughly $12. Looks like a lot of fun to service, being underneath the intake manifold. Ought to just do the VTCS removal when you service this, just for the hell of it.

Attachment 4677
Attachment 4678

#13 also leads to overheating of the motor of the pump itself, it uses the gasoline itself as a lubricant and coolant, lack of both lead to premature failure of the motor.

Also running at such low fuel levels promotes the formation of water in the tank, fresh air is drawn into the tank as the level drops, the more air you have in there the more water vapor as well, as the tank heats and cools over the day and night the water vapor can condense onto the inside walls and run down into the fuel, once in the fuel it settles to the bottom and never gets out unless sucked out by the pump. Most tanks these days are plastic so rusting of the tank is not an issue but this water can rust parts in the fuel pump, it also can be a home for microbes on the fuel/water boundary eventually sludging up your tank and plug up your pump/filters but this really only happens with diesel type fuels.

It seems weird that I haven't heard of any PCV issues in New Zealand. Maybe its a US/Canada issue.

Also add " raping your car when cold" & " shutting off your engine straight away after giving it death" to the list