I have a Mazda Millenia 1995 that will die OCCASIONALLY when at slower speeds - ie 20 mph or less with no hesitation or warning. Just dies.

Headlights, radio, and all electrical do not even flicker.

On the highway at higher speeds - feels like it dies, but if you let off the gas, the rpms level out. You press on the gas - which is the automatic reaction to a car that suddenly slows down - and the rpms drop and it gets closer to dying.

Let off the has again and the rpms pick up (or stop falling as fast) It;s difficult to describe because the car is slowing. When I get the rpms down low and the car has slowed down to almost a stop, it dies.

Here's where it gets weird.

Sometimes, whatever is causing this only lasts a fraction of a second - then it just picks back up and runs like normal - like for 50-100 miles. I just went two days without the issue to find it pop up again today.

Sometimes it just does whatever it is doing for a few seconds then picks back up. Sometimes it just does it until the car eventually dies and then I have to restart it - and it starts just fine. Sometimes it dies then takes 5 minutes to start.

I just drove it for two days almost 250 miles intentionally doing everything I could come up with to kill it. I drove 80 mph for 30 miles, went straight to bumper to bumper traffic for 45 minutes, drove another 30 miles at 65 mph, more bumper to bumper top and go, put it in my driveway with the emergency brake on IN GEAR and let it sit for 20 minutes, and drove it another 40 miles.

I PUSHED this car and it wouldn't die. Then today it has died 4 times in 20 miles.
Temperature has no effect. Coolant temp can fall anywhere. Nothing else comes up on my scanner that is consistently the problem.

The scanner picks up the open EGR boost sensor circuit since I pulled the thing out 2 yrs ago and it won't capture any other codes after that.

So my thought was distributor - but I replaced with a new one but still stalling. So now I am leaning towards fuel pump.

The problem is weird and I cannot nail it down. I also can't afford to just start replacing things till I get the right one.

Any help or similar experiences could really help. This is very odd. I don't often go to message boards looking for help. I am usually giving it. But this one has thrown me for a loop. I need someone who understands this car better than me.

 

I have the answer! And I spent a bunch to find it.

The main relay is bad. I hadthe exactproblem on my 2001, 2.5 L. Even down to the detail of the intermittant way it occurs and letting on/off the gas to level back out.

The main relay is the yellow colored relay in under-hood fuse box that is located near the battery.
Remove the cover and you'll see the fuses and a variety of relays, the main relay is the only yellow colored relay. It controls a variety of 12 volt power feeds to the ECU, distributor and other engine controls. The relay coil fails intermittently and this chatters the contact points that interrupt the 12v supply to the ECU and distributor this produces the driveablity troubles you are describing.
This is a DENSO brand relay on my 2001, the P/N on the relay is JE16 056700-8780. Please confirm for your year.
My car did all of same things yours is doing along with turning on the check engine light for a variety of transmission codes that set because this relay flickers on/off just as you describe.

I tried the distributor first too, it's not the distributor. Spent $600.00 at my Mazda dealer they didn't find the trouble and another $500.00 at a transmission shop chasing the check engine light, to find out the transmission was OK. Finally I took it to an independent shop and they found it by good diagnostic work.

This relay is around $100.00 from Mazda, but it will cure the symptoms you describe.

Hope this helps and saves you the $$$$$ I spent chasing this!

 

Thanks Mitsumazda64 for sharing your experience and the solution for resolving the mysterious Mazda problem.. I would be greatly happy if this could fix my Mazda problem. I'm replacing the relay fuse today and will let you know how it goes.

If it works, I will keep sharing the news to everyone on every car forum I know with this problem. Give me 2 weeks from today to post my result as I need to drive the car to make sure the fuse has fix the problem.

 

I have had the same problem with my 2000 Milly S. Do you know if the master relay is in the same place and is also yellow in the 2000 S model? I have also had intermittent transmission codes and lights. Could that be caused by an intermittent relay? Thanks.

 

I can almost give you an 100% solution, I had the issue with my 95 2.5 milly, its really simple if you dont have the money to get it completely fixed. Disconnected your EGR Sensor.
1. Open your hood.
2.Towards the back and middle of the firewall, there is a wire there, unplug it.
3. Turn it on!

That should be it. I did that to mien and i haven't stalled for 1500 miles! (I keep count lol)

 

This sounds very similar to what is going on with my 2001 Milly 2.5L. Ihave pastedbelow the descriptionof what is happening withmy Milly. I just don't want to start throwing parts at the problem and spend a bunch of money. Can Ipossibly havea badmain relay???

I just recently purchased a 2001 Mazda Millenia 2.5L (beautiful car). Upon driving itI noticedit ran rather rough as in it was"missing". Open the hood "whala" still had the OEM spark plugs, wires, distributor cap and rotor at 105K.After changingthe spark plugs, wires, distributor and rotor, as well as dumped some Lucas FuelTreatment into the tankon a couple different occasionsfor preventative sake.
It ran much better than before (after changing of aboveparts) but it seemed to still "miss"or run rough but ever so slightly, to the point it wasdifficult to isolate. It would slightly jerk on take off not that "jerking take off" that seems to be common with these cars as I've read but different.
I tried to reproduce the "jerk" on take off buthave not been able to. Whilesitting at idle it runs smooth over all, the RPM needle doesn'tmove at all but you can still feel the roughness and slight "missing" indicating there's a problem.This has gradually gotten worse as my MOTHER got in the car and said its such a beautiful car but its "missing". So I pulled up the firing order for my car on the internetand made certain I put the wires back on correctly...no problem there! I then reseated all the wires in case there wasn't a good connection.

After doing that the ce light came on (ce light hadn't been on prior to this)...I zoomed up to the local auto zone and had them check the code...P0300!Random cyclinder misfiring! Well...whata you know! (Glad to see it's staying on topof things). Onmy way back home my carshut off on me while I was sitting at a traffic light...its NEVER done this while I've owned it!I considered takingout the spark plugs and checking whether they are allgapped properly as the counter person who sold them to me said they were pre-gapped for my engine already.

Also, I thought maybe itcould be the fuel injector(s) or a pesky vacuum leak but listened and checked for that...nothing! IS THERE A WAY TO CHECK THE MAIN RELAY????

 

To check the main relay it is very simple no one ever thinks of it, simple pull the relay out whit the car on, then push it into the slot but dont put it all the way on, if the relay is good you will hear and feel it click. (Just make sure the key is ON) then you should be good to go with that problem. However, I still think you have an EGR Booster failure. You should try unplugging your EGR Sensor.(I had the same codes come up on my 95 milly and I disconnected the sensor till I can get it fixed, its been running for 2500 miles now.)

 

Thanks for you prompt reply. This has been driving me crazy trying to figure this thing out. Did you have the same symptoms I described with your 95 Milly 2.5L? Also, do you know where the EGR booster is located on my 2001 2.5L? Where do you unplug the EGR sensor on the 2001?

Thanks again!

 

Yep, same exact issue and i spent a lot to find it. Right in front of the firewall under the hood there should be a plug, its towards the middle of the firewall, right on top, just simply unplug that wire, its just a simple clip. I took a pic of mine to show you guys.
http://s19.photobucket.com/albums/b1...t=Image002.jpg
http://s19.photobucket.com/albums/b1...t=Image003.jpg
http://s19.photobucket.com/albums/b1...t=Image005.jpg

 

I have a 95 milly s 2.3L i am having the same problem but from what i read all of u guys have a 2.5L is it still the same valve? if so wer is it on the s?