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)
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,
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.