I'm almost at 80K and yesterday morning after work I got in my 06 Si started it and the sound the engine made was different and when you know your car you notice little things. The sound itself wasn't too different from the original way it sounds, but it was "rougher" like the way your voice changes when your get a sore throat. I let the car run on idle a few minutes and it started to fade away but not completely, or maybe i was just paranoid from that point on. The car is driving fine just like it did before I noticed the change of the engine sound.

What can be causing this, should I be worried?

I have to say that only the regular oil changes have been done the last 40K miles and none of the recommended dealer's maintenance following some of the advice I got on this forum.

Common sense tells me to have the car checked, but I dont wanna be tricked by the dealer into checking and changing things that have nothing to do with the problem. I was thinking of taking my car to a shop in town run a test on the engine and see what they say THEN get a second opinion from the dealer and if the problem (hopefully there is no problem) is the same then go with whoever can do the job for less.

Please I need some suggestions on how to go about this.

 

Has the sound changed at high RPM?

 

Check all your fluids then take it to a shop if you can't find anything

 

I would suggest you to take your car to a good technician.

 

Perhaps you have a plug giving up, that would give you a rougher idle with the richer fuel mix on a cold engine.

It is not that bad of a job to pull the plugs.

 

Check the plugs and wires.

Rough idle is caused my many things...