I've recently noticed a pinging type noise when I accelerate b/w 3K and 4K rpms, kinda sounds metallic. I always use 93 in my Max and had a tune-up done last year at 106K, currently at 128.3K. What can be the cause of the ping?

2nd, I performed a bounce-test on my Max, there's an old-matress type noise coming from the front area, this happens even when I get into my Max. I can also hear it going over bumps. What can cause the "old-matress" syndrome?

 

the old matress sound COULD be your seat....mine does it if the lumbar is up

as for the pinging... - how loud is it?
are you 5spd or auto?
cant you leave it parked...rev it up and hear it? or is it ONLY while driving?

 

I'm an auto, the pinging happens while I drive

 

Have you replaced the knock sensor?

Apart from that I think you have a suspension problem? What is the condition of your shocks etc?

 

knock sensor was replaced Jan. '05

suspension-wise, everything is still original

 

the rubber mattress noise i had on my car was caused by deteriorated rubber spring covers..they were rubbing on the mount

 

have someone listen down by the struts when u bounce the car- if it squeaks then, then itd time to buy new struts or troubleshoot with a bootkit to try and save money.