hey all...i have an 04 i35, 81k....when accelerating at around 1500-2500 rpm, i hear a noise coming from what i believe to be under the car, although it could possibly be from under the hood but def not near the front of the car....it sounds almost like marbles in a metal can....its getting progressively louder over the last few weeks. i have no cel, and the car is running and shifting fine. anyone ever have this problem before?

 

Check level of motor oil and radiator fluid

 

Could be your cat breaking apart.

 

It sounds like common rattling issue because he has it specifically at 1500-2000 rpm

 

oil and radiator levels are fine i checked........and if the cat was breaking, wouldnt it do it all the time? one thing i forgot to mention, the noise is ONLY when im accelerating. the second i take my foot off the gas the noise is gone. press the pedal lightly again, its there. if i hit the gas in park or neutral, i dont hear it either. im hoping i dont have a tranny issue.

 

Yep. It is the rattling issue. I have the same thing once in awhile. I think it happens when car overheating a little because it sound worse if you have low oil or low radiator fluid. Not sure why it does it, but thats my personal experience

 

It's a heat shield.

Jack up the car and pound on the exhaust with a rubber mallet. Go up and down the system and eventually you'll hear the noise.

You can either cut the shield off, or take a hose clamp and snug it down tight. It'll come back though as the clamp loosens over time.

I haven't had the issue on my i30 yet, but every other car I've owned I've ended up yanking them all off. Doesn't seem to hurt anything.

 

I have the same issue on mine - it only happens between 1500-2000, and only when there's a load on the engine. It's particularly noticeable when going up hills, but cant duplicate it when the car is parked. Will check the heat shield

 

Guys I hate to tell u this but its ur cats converters . My friend has the same problem . On his 03.. The sound is like when u put a regular gas in a performance car u get a engine knock . The reason why it sounds like that is because the rock inside the cats have broken apart inside the cats.. In my friends car its the cats on the exhaust manifolds . Its a $1200 fix if u dont want to hear it no more !! Look at my post that says need advice .

 

I believe the "common rattling issue" is different. A much higher frequency rattle - more like very small wind chimes rather than marbles in a tin can. I'm leaning more towards the idler pully for the belts.

 

I'm not an expert, but I've been wrestling with this same issue for the past 2 years. It seems to be common for i30/35 2002-2004 and even some Maximas.

After a few visits to the dealership and some local mechanics, I turned to the internet. People were pointing towards the MAF sensor and the throttle body. After cleaning both, my car ran flawlessly. Not only did the jingling/rattling go away; my car ran as smooth as when I bought it new. But this only last for a few days.

Then I tried changing the MAF sensor. The engine ran more rough, the jingling got worse, and I got error codes P0171 and P0174 (i.e., too lean front and rear banks). I went back to my old sensor and cleaned it. Again, ran great for 2 days.

Although I haven't found the solution yet, it seems the problem may be an incorrect air/fuel mixture causing the throttle valve to jingle. When I first clean the MAF sensor and the ECM hasn't completed relearned the new settings, the car runs perfect.

Now that I've tasted how smooth the car can run, it's driving me crazy! =)

Does anyone have any ideas on how to address this?

 

hmmm....this is interesting bc i had a p2135 code not too long ago (throttle position sensor).....i had a bad battery and the cel went off after changing it. since then is when the noise has gotten louder.