Thanks for the great fourm. I have a 04 Mazda 3 which has been great. About 4 months ago it wouldn't start - cranked over fine, battery and starter good, it just wouldn't catch... no spark or no fuel I guess. Checked what I think was the fuel pump relay and it seemed to pull in properly. After waiting about an hour it started. Weather wasn't particulary hot or cold or damp. Started fine, no probelm for a couple of months. 2 months later it did the same thing when trying to leave work, had been sitting all day, same as before. Started up after about 1/2 hour wait, started fine in daily driving for the next couple of months.

Last week it did it again, but wouldn'tstart after several hour wait. I got a ride home and left it overnight, came back in the morning and it wouldn't start... so I thought"great", maybe someone can figure it out this time. Had it towed tothe shop. When it got there it started. Damn! Mechanic said no way to figure it out when it'sstarting OK.

Anyone have any ideas? I really like this car but can't stand the uncertainty...

 

I haven't heard of that one.

Do you ever get any CEL's thrown? (Check Engine light)

How many miles on the car? I assume you're out of warranty.

Not sure why you'd have an intermittent issue like this. I'd say intermittent ground, but you state it cranks just fine. Take a look for any kind of corrosion on any wires (white powdery residue.) If you find any, clean it off with a wire brush. Pull out the fastener and clean under it if possible.

Maybe change the fuel filter, although that shouldn't cause an intermittent problem. You can check to see if you are getting proper fuel pressure. Hook a fuel pressure gauge onto the fuel feed rail, there should be something that looks like a bicycle tire air fitting. Crank the car with this gauge hooked up and take a reading. If you've got fuel there, you should have it at the injectors. It would be very odd for all injectors to go bad (or be intermittent.)

 

It has the feel of something electrical -a looseconnection or bad part.

You could try poking around and making sure all the ignition connections are clean and tight,

If they put your car on thediagnostic, maybe they'll see something. Acouple years ago, on anon Mazda, I had a problem likeyours which ended up being a baddistributor cap.

 

As your problemseems to affect the entire engine (not a single cylinder which would just make it run rough.)

I would try replacing the ignition coil and see if the problem returns. The part is very easy to change out (a couple small bolts and a plug)

In the Mazda6 factory service manual it gives a diagnostic procedure to test your ignition coil.

Go to your local dealer and ask if you can make a copy of the pages in the 3 manual that show removal and diagnostic of your cars ignition coil. (Engine Electrical System section - Ignition system sub-section) I could give you copies of the 6 manual, but they may not be correct for your car.

 

It sounds like the electrical problem the 04's have. I was reading some reviews about it just last week. I've even heard of it happening driving down the road, car will just shut off.

 

I don't know, but I have had this problem on TWO (non-mazda) cars that I have owned (one on a car I currently own) - and it drives me crazy! Never happens when it's in for service, only every once in a while.