Nanky

I have been hearing what I would describe as a rattle sound coming from the engine of my '07 when I am driving in low gear. There are some steep streets where I live and the sound is louder when I am going uphill or starting from stop, and also on an incline. It almost sounds like loud valve chatter at times but I am not sure. The dealer tells me it's a result of the Costco fuel I use. I switched to Chevron a while back however, it's still there.

Input from anyone with some insight as to what could be happening would be greatly appreciated. Thank you!

Strigoi

Does it happen when the engine is only under certain loads or is it there all the time?

I have a bad secondary cat right now and it kind of sounds like what you're describing.

Nanky

I don't hear it all the time. Every now and then, I will hear it for a brief moment when I am not going up hill. It is when I am going uphill that it's almost guaranteed to happen. I will look into the secondary cat to see if that could be the same issue I am having. Thank you...

VictoryRoadPerformance

Do you hear it for a moment on start up and then it goes away? if so it could be a camshaft adjuster http://vrpspeed.com/index.php?route=...product_id=348

Nanky

Thanks for the information. I haven't heard it on start up. I hear it mainly when I am going uphill in low gear. I can make it happen when I deaccelerate and accelerate in 2nd and 3rd gear in the 25-30 mph range. It goes away as speed picks up or stays for a while if I maintain speed in that range..