2004 Mazda3 5-Speed - Engine

Hi - I’m a mewbie (be kind). The problem is that for the past several months I have notice the engine is much louder than it used to be. I can tell no real difference between third, forth and 5th, although the TAC shows usual RPMs. It sounds like it is in third for all three gears. I’ve asked the dealership and a carophile, both drove the car and pronounced it fine. It isn’t! Has anyone had this experience? Please help!

While we can’t hear the sound itself, if you describe it, we’d have a better guess. It could be something as “insignificant” as a loose heat shield or you could have a hole in the exhaust pipe somewhere. If you live in the rust belt(where it snows and they use salt on the roads), then 6~7 years might be about the time the exhaust pipes get rusted out.

If your rpms are “normal” at various speeds (based on your prior experience) then it must be shifting into the top gears. If not, your rpms would be much higher than normal. I would also start by having the exhaust system checked. You can do a simple test yourself – start the car, then plug the tailpipe with something. If the car does not stall out right away, then you have a hole in your exhaust system somewhere.

That is what I think is so strange, that the tac shows normal rpms but the engine sounds like you are driving 60 in third. I will try the exhaust test. I assume I should use a wash cloth or rag. I’m going to try this evening. I will report back. Thanks so much!!