I have a friend who has a 2001 Millenia S with around 72,000 miles on it. She has taken extremely good care of the car. She had to replace a timing belt last year, but other than that has had no problem. Suddenly about ten days ago the car would be difficult to start and would run rough for a few minutes. But it was intermittent and she couldn't really define a pattern to the problem.

She took it to a local Mazda dealer and they said it needed two ignition coils and also had a vacuum leak. I'm no expert on ANY car, let alone a Miller-cycle engine, but the vacuum leak sort of made sense to me.

Anyway, she went to a local mechanic who also had the proper equipment to diagnose the 2001 and he said it was a vacuum leak and one coil. She let him do the work and picked it up on Friday. She drove it that afternoon and evening with no problem at all. Suddenly on Saturday it started running rough all the time and she says it is far worse than it ever was. She took it back to the mechanic who said it needed a second coil after all.

None of this makes sense to me. Why would it run fine for a day, then worse than ever if the second coil was bad. Is it normal for a mechanic to remove the coils and check them? I could see where they might have let one of them get dirty and have it go out the next day, but again, it's really not making much sense.

I'm worried it could be her catalytic converet. I did read the Millenia threads coils and saw one of the long posts about 2002 converters. But I could find nothing about this. I've asked her to take it to Autozone for a readout but it's at the mechanics right now. The dealership didn't give her the codes so I can't help there.

Any advice would be GREATLY appreciated.

 

we have 2 99's. the black one we have had since new. couple of years ago, ce lite come on, we took it to the dealer. vacuum leak, broke tee, cost 564. couple months later, bad miss, random missfire, then showed at least 1 bad coil, i dont remember exactly how many. since my wife drives this car, i cannot take the chance of her being stuck on the side of the road, so i bought all 6 new coils and changed them out. i had just done the plugs, so the work was very similar. i have since tested them, the ONLY way i know how, which is to install them on the front bank, and run the car. the front bank is really easy to get at, probably takes 10 minutes to get a coil out. but 2 of them were bad. last year i bought another 99, and going thru the records, i found an ro for vacuum leak, except it was under warranty, and done for free. the rear bank of coils gets more heat than the front bank, and also the rear bank takes like 10 times longer to get at. i think it is very possible another coil has gone. coils dont like heat. the black car had about 70k when the coils were changed. it now has 83k, the white one has 78k. both our cars are extremely well maintained. yearly brake/coolant flush, synthetic oil every 5k, both cars have had new axles, fuel filters, brake pads, couple of traction rods, ball joints, seat heaters, horns, i consider the maintenance on these cars much higher than others we have owned. however, we really like the cars, and we will probably drive them till the wheels fall off.

 

Thanks,

I guess the bottom line is that it's not as unusual as I thought. I had heard that it was smart to put "questionable" or older coils up front, but I can barely work on my lawnmower, let alone the '01's engine.