Dear Mazda Protege Experts,
My son's 2001 Protege 1.6 liter car developed an odd symptom. At highway speeds, it suddenly hesitates (sometimes when the automatic transmission is changing gears). Took it to the dealer for a diagnostic test. No error codes were found and they weren't able to recreate the symptom on their test drive. I've encouraged him to take it back to the service shop for a more extensive test drive, but has this happened to anyone else. The car has 120,000 miles on it. We recently replaced the spark plugs, wires and coils thinking it was an ignition-related issue. Thanks.
Mike

 

Okay, over 50 views and no one has any ideas as to the possible cause of this problem?

 

Mimi: there is not much to hang your hat on in the description of the symptoms. It could be anything.

You may have to cover the basics first:
Electrical: make sure all ground connections are good, in particular around the battery and the alternator. Disconnect and reconnect all wire harnesses you can find. Inspect the connectors for corrosion. Just disconnecting and reconnecting may improve the contact. If you are lucky you may find one that's loose.

Check for vacuum leaks at the intake side. In particular the air intake hose near the accordion section. Bend it to check for cracks.

Fuel delivery: fuel pump, fuel filter, fuel pressure regulator.

Good luck to you, I believe you may need it.

 

Thanks Tan Protege.