Idles Rough, Misfires, and Possible Check Engine Light on Mazda Protege

A loose or corroded ground terminal on the driver's side of the cylinder head can cause a rough idle, misfires, and there may be trouble codes. Restore the ground to the cylinder head.

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Average mileage: 141,626 (60,000–243,000)
Engines affected: 1.5L 4 Cylinder, 1.6L 4 Cylinder, 1.8L 4 Cylinder, 2.0L 4 Cylinder
14 model years affected: 1990, 1991, 1992, 1993, more1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003
33 people reported this problem
problem details
2000 Mazda Protege - 1.6L 4 Cylinder 128,000 mi,
Rough idling, sputtering upon startup. Rough when driving. Blinking check engine light.
2002 Mazda Protege - 2.0L 4 Cylinder 156,000 mi,
Check engine light flashes somethings then stops..does it randomly more on the highway. Then sometimes check engine light stays on. Seems to lose power only when check engine light flashes
2000 Mazda Protege - 1.6L 4 Cylinder 243,000 mi,
Car has rough Idol and often stalls when stopped. Haven't fixed yet but this sounds like a possible solution.
2000 Mazda Protege - 1.6L 4 Cylinder 146,897 mi,
My woman's protege is having the p0300 code I changed the plugs and wires just for good measure but it didn't change anything I cleared the code and it started the rough idle and surging at highway speed pretty much around 45 mph . Gonna change the coil packs and clean the throttle body and MAF sensor hopefully it will clear this mess up.if you have any ideas let me know . Too many forums with useless info about this code .
1990 Mazda Protege - 1.8L 4 Cylinder 60,000 mi,
Idles Rough, Misfires, and Possible Check Engine Light.
1999 Mazda Protege - 1.8L 4 Cylinder 145,100 mi,
Idles rough, check engine light blinking
1993 Mazda Protege - 1.8L 4 Cylinder 170,000 mi,
Idles Rough, Misfires, and check Engine Light gas out tail pipe ...bad smell
1999 Mazda Protege - 1.6L 4 Cylinder
idels rough and cuts off
1998 Mazda Protege - 1.8L 4 Cylinder
OK I have a 1998 mazda protege that had a blew head gasket a broke timing chain and a the timing belt got caught and also I had a warped head so I went about getting all of these problems fixed by myself by so I bought every thing that I had need and replaced everything by self and also had my heads shaved down so I recently put every thing back toghter And it is idling high and over heating very quick I made sure I timed every thing dead center in don't know real what could be my problem with the car is need some were to start
1990 Mazda Protege - 1.8L 4 Cylinder 145,000 mi,
Idles rough. Sometimes it will run rough when not at idle. Check engine light will periodically come on then go off after a while. I checked the spark plugs. They looked fine except the gaps were all off. I regapped and still had the same problem. Plug wires have been replaced recently as well as the valve cover gasket. I have also cleaned the MAP sensor several times which seemed to fix the problem initially.