Hellow fellow Mazda enthusiasts,

I have a 1996 Mazda Millenia S, with 165,000 KM on it. I also recently had the engine rebuilt (a spark plug broke in cylinder #6 while driving and caused internal damage).

The issue with the vehicle since a couple of days before the broken spark plug and the subsequent rebuild, and even now after the rebuild, is that it is hesitating under medium to heavy acceleration. Under low acceleration, or accelerating while gowing downhill is not an issue. However, if the car is going uphill, or if I accelerate halfway or more on the accelerator, it will hesitate, and have very little power and will gain speed very slowly. If I back off the accelerator, it find a sweet spot and starts to run normally- but not spee up. But if I step on the gas it hesitates and slows down again. Error code P0301 came up once. the coil was replaced, plug was checked, error code is gone, but the issue remains.

Here is what I have done so far with no avail...

1. Replaced fuel filter... old one could have been clogged
2. Replaced air filter
3. All spark plugs are brand new and have been inspected by mechanics to verify they are good
4. Error P0301 came up once, the coil was replaced by Mazda dealer but the issue continued.
5. crank sensor air gap verified..ok
6. Oxygen sensor removed and car run without it, same issue (i.e. mechanic at Mazda says is not the O2 sensor)
7. Throttle position sensor verified.. EGR valve cleaned and checked and is ok
8. Catalytic converter removed and issue persisted
9. Fuel pressure checked and verified is OK
10. Fuel injection service performed and the issue did not go away
11. Dyno testing done and no issue found during the dyno test.
12. There is no smoke from the engine during running, and very minor smoke when starting the car after its been sitting for a few days. I suspect that this smoke is from the Lysholm Complressor internal seals aging which is common after 10 years life on these cars.

The dealer is saying they dont know what else to try, other than buying a new PCM computer for it which is a lot of $$ - and that may not even fix it.

The curious thing is that the car revs freely under no load...i.e. when in "Park/Neutral"... and does so really well. It is only when it is being driven and is under some load acceleration or going uphill that it 'misses' and loses power. I have spend close to $4000 on the rebuild and the diagnosis and am getting no where. please help if you have any ideas!

thanks to anone who has thoughts on where I could go next!!!

Cheers

Helmi
"MilleniaMan"

I'm far from an expert, keninn and babyhuey are those. I just know there seem to be some common vaccum leak problems with the Millenia that others start with when trouble shooting the system. I have the same thing with my Millenia S and smoke on startup and agree with your assumption. Since you said you have 165,000km I can only imagine you are from Europe, Australia, or Canada which might make my next thought a little more difficult.

When you are driving and notice the hesitation do the RPM flutter or can you "feel" the engine hesitating or misfiring?

I hate to ask this, but have you possibly thought about sourcing out a new engine if you REALLY want to keep the car at this point? I have seen quite a few 40-80,000mile engines on eBay for like $1200-1500 shipped. Was just a thought.

Thanks Hadrien,

I am in Canada; but the car is the same as the US car other than the speedometer!

When the car hesitates, it gets stuck at whetever RPM it is at.. the RPM's dont go down, its just that they dont go up either. Feels like its missing and it will attempt to accelerate and when the engine speed catches up with the pedal the car takes off like normal again. Almost like the Lysholm is switching offf.. then engaging.. then switching off... and finally kicking in.

As far as used engine goes, this rebuilt engine is great upto block-ring-piston-cams-calves-head etc. Its the anciliary stuff that I need to fix up. A new engine block with the same hoses, Lysholm, electronics and sensors I am afraid will do the same thing.

My suspicions are the issue may lie in... Sensors, ECM in how its controlling air/fuel mixture, or vacuum hoses. Are there any vac hoses attahced to the Lysholm?

But there are many on this forum with real indepth experience on MIllenias, they may have come across something like this in the past so lets see....

Cheers,

I recently contacted MilleniaMan to see if his issue was ever fixed because I also had a similar issue but on the 2.5L Millenia. He replied and said that it was a coil on one of the cylinders. Replacing it fixed the problem.

This bit of information completes this thread with a solution. I figured there are people out there who'd like to know.

I too have exactly the same problem with my Mili 2.3 S 2001. At idle or park it revs up great, under a load or any movement on the accelorator the TSC light comes on and it starts missing. Changed 1526 and 1525, fuel filter (showed alittle dirt/rust), checked all the vacume hoses twice, changed plugs, fuel, put heat in the tank, ...

Where is the Lysolm sensor located?
Where is the EGR sensor located?

What else could it be. Heinz

I too have exactly the same problem with my Mili 2.3 S 2001. At idle or park it revs up great, under a load or any movement on the accelorator the TSC light comes on and it starts missing. Changed 1526 and 1525, fuel filter (showed alittle dirt/rust), checked all the vacume hoses twice, changed plugs, fuel, put heat in the tank, ...

Where is the Lysolm sensor located?
Where is the EGR sensor located?

What else could it be. Heinz

that sounds like a weak coil. what plugs/gap did you install? when the tcs/tcs off lite comes on, does the ce lite up too? if so, what codes?

Hey Heinz how Ironic my name is also Heinz and i own a millenia and i had the same problem. my problem got fixed by changing the spark plugs and pug leads. solved my problem. the TCS would go on and the car would not accelerate past 2500rpm. Now no prob!! check out my ride car domain LUXMILLy

Go with Heinz. The ignition harness on Mazdas is tempermental, and so are the plugs and gaps, so don't waste your money on 3rd party knock offs.
You can have what you think is a perfect looking spark off the wire or plug, but once working in a compressed mixture on a loaded working engine, the spark is not man enough for the job; there is a big difference between sparking in air and sparking in a 120 psi. environment.

My Mazda Millenia S 2001 is in great condition and runs nicely but the air bag light on the dash is blinking; it started suddely 2 days ago. What could cause this ? :(

Dude, that is called THREADJACKING.

You are starting a new conversation in someone else's thread. A Big No No

http://www.youtube.com/watch?v=B9q2jNjOPdk

Are these cars automatics? If so, an engine misfire will put the transmission in limp mode to protect the engine, and you will not be able to get top gears or overdrive.

Also, I forgot a couple of real dumb things that crop up so rarely they are overlooked (by me at least).
!. Pull your PCV and shake it. If it rattles, good; if not, replace.
2. The whole ignition system performance hangs on an inconspicuous black rectangular box thing called a capacitor hooked up to the + line of the coil packs on one side, and grounded to the engine at a point near the coils somewhere.
When the coils are triggered, the pulse current is too heavy and rapid to be efficiently supplied via all the wiring going back to the battery, so that capacitor works like the flash unit in a camera, temporarily providing a short direct path for the huge current pulse essential for a hot fat spark. If that sucker goes open circuit, the spark will be seriously degraded on all the coil units it supports, and it does not show up as anything distinct, just contributes to a general malaise and misfire under load situation. It is not expensive to replace.