I have had this car into the dealer 6 times and into 3 private shops bit to no avail. The check engine light stays on because of a miss code and now two oxygen sensors. The different shops have replaced the plug wires wice distributer, plugs twice, timing belt, fuel filter, charcoal canister, two different vacuum lines. I now have two bad oxygen sensors from the missfires. It is random. no pattern whatsoever. When it starts it progresses to continue the missfires even at highway speeds. I have over $1800 into the problem already over the past year. The missfires increase if I run 92 ocatane or higher gas. The missfires do not occurr everyday. It has its good and bad days. I am frustated to no end. Can anybody help me? Mazda sure can't.

Do you know if the shops are using Mazda wires, distributer cap ect? If not that could be a problem. When they replaced the distributer did it come with a new rotor or did they use the old one? If they did replace it was it a Mazda rotor? You can also check the resistance on the ignition coil, the specifications should be in a chiltons or haynes manual.

All parts were replaced with Factory Mazda parts. The rotor was also replaced with Factory Parts. Also the Mazda dealer cleaned the connectors to the computer under the console. It is right in the leak zone of the cup holders. It was to no avail also.

Try the following:

Replace the ignition coil. Clean the wire terminals to the coil and to the distributor. Get about three bottles of Techron (Walmart sells it)and poor one can at a time with about 7 gallons of gasoline into your gas tank. Do this three times. Techron helps to clean carbon out of the engine and injectors. Clean the throttle body. You may have heavy carbon deposits there. This can contribute to rough idle.

The Carbon has already been cleaned from the heads by one of the shops. Have you seen problems like this by the ignition coil before. The dealer is sayin now that I need to replace the Mass air flow and it could possibly be even the tranny. I don' believe it could be the tranny. The problem is also now getting worse. It is missing terribly at first start up after sitting overnight and also it seems to get worse when the car first reaches operating temperature. Then it seems to go away. Thanks for the suggestions sofar.

Other areas you can check are fuel pump pressure, EGR valve operation, do a compression check, check the operation of the fuel injectors. With OBD-II the repair shop should have been able to pin point your problem.

Don't mean to get anyone's nose out of joint,but how about we try to DIAGNOSE this problem, instead of telling him to check every part of his engine!! It would appear that the mechanics have done all the obvious things, and then some!My money is on some sort of vacuum leak, but exactly where, is a bit hard from the other end of a computer! Sometimes these problems need to be a bit more hands on!!

I understand where your coming from, but the repair shops haven't found the problem, and I assumed he wanted areas that he could check himself.

Hey guys I appreciate all your help. I am taking the car tomorrow to my friend that is a mechanic. He has looked at the car once. He also said it sounds like the mass air flow but is also going to check the fuel pressure and ignition coil. I am just tired of paying to have one thing replaced at a time. Mazda actually told me to just drive the car until it broke, then they could find the problem. Simple logic, I guess these the ignition coil and mass air flow are the only two things left to replace. The weird part is that the car acts normal most of the time. It has been running like crap the past two days. It almost acts like it has water in the gas. If any of you can think of any thing else to check, please let me know or if you live near Charlotte NC and want to see if you can be the ultimate mechanic and find the problem, please let me know.
Thanks, I'll let you guys know what my friend finds.

I have replaced the Mass air flow by the dealer... still not fixed...

Now the car wont turn over when it sits out in the 30 degree weatherovernight. Have an appt. this Monday for that. Let me know, I want mine fixed

When the mass air flow meter went on our '95 626, the car ran too rich and the converter got plugged up. A dealer should be able to get to the bottom of your problem.

I am randomly missing cylinder 5, and originally found that both my plug was bad and the plug wire on 5 was split and it was arching in the plug well. I had them replaced those and after 1000 miles it started again, same code, missing cyl-5. This HAS to be an electrical problem. either the coil or the distributor/rotor. For me it sound more like the distributor or rotor since the problem is always on the same cylinder, if the cylinder is random then it's more likely a piece common to all, the coil... I wouldn't waste time with the mas air sensor.

I have this problem on my '91, 929S. Idles rough and rough upon acceleration, like it's missing. My ignition coil resistance is 1.4 ohms instead of specified 0.8 ohms. The secondary is OK as specified. I've replaced plugs and dist cap with no help. Any suggestions? How did your's finally got fixed?