I gave this a severe rating because it could result in an accident.

This problem has occured in specific weather since the car was new (purchased in May, 2008, first occurence in December). The problem occurs regularly in very wet after a period sitting outside in well below freezing weather so that metal surfaces are dripping with water (road surface often has sections of wet ice). These are exactly the conditions when carburetor icy would occur in the good old days. Engine dies around the time the temperate reaches the normal level. With clutch in RPM drops to zero, but engine restarts after a couple seconds using clutch or starter. This cycle repeats many time and is dangerous if engine cuts out while car is on a section of wet ice or when trying to cross a snow-plow bump merging onto a main highway. IN the first two years, I had the following codes:

PO301, PO303, PO304 -- replaced #1 and #3 coils PO303 -- replaced #3 and #4 coil and 2 plugs PO303 -- replace purge valve PO302 -- replaced #2 coil and a plug PO455 -- replaced purge valve PO455 -- replaced purge valve

Since then the dealer has continued to replace plug and coil packs, but none of them have shown any signs of burning or other damage. The fact that the engine runs well with the CEL on suggests to me that the plugs and coils are OK. The variety of codes suggests to me that the problem is not ignition or air supply but the data getting to the computer.

In the latest episode, after about 5km the check engine light (CEL) came on (steady, not flashing). Once the CEL was on the engine ran well, as it has in the previous occurrences. This was Monday morning. I wasn't able to get the car to the dealer until Thurs. Thurs AM the CEL was off, but dealer found a number of codes indicating misfires in multiple cylinders. Previous occurrences have given either random misfires or consistent misfires. The mechanic tried swapping the plugs and coils around but continued to get multiple codes. He replaced a distorted gasket on the MAF. The car has Krown rustproofing, which is always applied in November so shortly before the first time the problem occurs each winter, so the dealer suspects the rustproofing may be getting into the air supply. I also have a 2007 Mazda 5 with 2.3L engine that experiences the same weather and same Krown regime and does not have the problem.

I'm stuck with a car no sensible person would want to drive in carburetor icing weather. I think the dealer has made an honest effort to resolve the problem, but has been unable to find the root cause. In the past they have provided a loaner and kept the car for several days without encountering the problem. If I could afford to turn the car over to the dealer for a longer period they would have a better chance of seeing the problem first hand, but in view of the potential for an accident I'm not sure that is a good plan.

Motor hesitates briefly, anywhere between 2500-3500RPM, under mild/moderate acceleration. ("Granny" acceleration doesn't reveal the problem. Neither does "hard" acceleration.) Happens in any gear. Most noticeable using cruise control "+" button to accelerate on freeway.

IAT and MAF cleaned - no effect. May be the EGR valve, one of many known failure points with these cars. $600 job...

But as long as it runs, I'm not bothering with these issues any more. Because I now hate this car, ever since all these problems began as soon as the warranty expired. I guess Mazda learned GM's trick of designing cars to fail out of warranty.

Interestingly, now that I stopped babying it and started beating on it, no new problems have occurred.