Misfires under load (acceleration) can be caused by leaky spark plug boots. When a spark plug boot leaks, it allows the spark to arc, or jump, to the cylinder head. New spark plug wires will be needed.Google+
Car Problem Reports
Mazda Protege Misfires Under Load
Mazda Protege Problem
Engines Affected: 1.6L 4 Cylinder, 1.8L 4 Cylinder, 2.0L 4 Cylinder
Average Mileage: 120,333 mi (75,000 mi - 170,000 mi)
Visitor, 2003 Mazda Protege, 2.0L 4 Cylinder, 104,000 mi
Misfires only during heavy acceleration. This began after replacing one coil and 4 spark plugs. no solution as of yet.
Engine chugs, jerks or bucks. The idle is rough and car often refuses to start. It takes several attempts for ignition to take place. Got a P0304 code and replaced Cylinder 4 coil. Also adjusted the idle. Have yet to notice any results.
Visitor, 2003 Mazda Protege, 2.0L 4 Cylinder, 130,000 mi
Misfire under load. Bucking and jerking under load. P0304 and P0090 codes
Visitor, 2001 Mazda Protege
misfire code report, car stop,