I replaced all 6 coils on my 99 GLE (Thanks to all the help) and that got rid of my idle "bumps". I was hoping that would fix my other problem, but alas.

I experience this problem very intermittently, I can go weeks at a time without experiencing it, then it happens a few times per drive, then it goes away again.

When I'm in motion at least 20pmh, and I accelerate, I sometimes hear a metallic ticking noise. It's related to the amount of acceleration. Picture a wheel with a bent tab or something spinning. Every revolution the wheel makes the "tick" sound, so the faster the rev, the more ticks. When I let off the accelerator, this hypothetical "wheel" slows down, and the ticks slow down as well and eventually stop.

I can accelerate again and the ticks are gone. As I said, this is very intermittent -- and this "wheel" analogy might not be apt at all other than to describe the frequecy of the ticks.

Any theories on what could be the problem?

Thanks!

-Mike

 

could be lots of things..... what octane are you using? valves could be tapping, could be an exhaust leak... any number of things... I'm sure there are some people on here that have had your problem before...

btw, glad you got the coils fixed!

 

I always use 93, so I doubt its the gas.

 

Probably your lifters, does it do it on start up? What kind of oil have you been running, has it ever gone low.

 

1) What are lifters?
2) Whatever the shop puts in (I assume its non-synthetic)
3) No, but I did let it get dirty one time