Pinging/rattling in engine bay

[JuiceMachine]

I was just wondering if anyone has had this problem? When the engine starts to heat up and I accelerate I get a pinging/rattling (metalic) sound from what sounds like just in front of the passanger/middle part of the engine area. I thought that it might be the motor mount (as I was getting the shiny spots on the intake) so I changed the front mount. Still the problem persited. Could it be that it's the rear mount or possibly the tranny mount? It almost sounds like something is loose. The sound starts around 2000rpm but stops when I accelerate over 3500-3700 rpm. I also get a groan/grind noise when I start from a stopped position (usually about 1-2 seconds after I release the clutch).
If anyone has any thoughts please fire them my way! I figured I'd speak to the pros on this *grin*

 

[projectSHO89]

Check all the cat and exhaust heat shields to see if one is loose.

Check the cats by rapping them with a broomstick and seeing if there is an internal rattle (very bad if there is).

Might be a small exhaust leak at the exhaust manifold that heals itself when the engine warms up.

Steve

 

[JuiceMachine]

I checked all of the shields but the noise sounds more like it is coming from just around the firewall. I haven't checked the cats I'll try that but aren't the cats more under the centre console?
The sound only happens after the engine starts to heat up, it doesn't do it until about 5-10 minutes after it's been running. It's one **** of an annoying noise tho!!

 

[projectSHO89]

There are also heat shields on the exhaust manifold and on the Y-pipes besides on the cats. Crawl under there and you will see what I mean.

Steve

 

[JuiceMachine]

cool... I'll do that
Thanks!

 

[JuiceMachine]

cool... I'll do that
Thanks!

 

[Jayman]

What fuel are you using? Trying running your tank as low as possible and then fill it wth a premium fuel (91 octane or higher). If the problem still persists try adding a can of octane booster. If this cures the condition it is only a temporary fix, but I would be guessing you have excessive carbon buildup in the intake and on your pistons causing pre-detonation. Ford sells a kit which you can do yourself or have the service department do it. I don't remember what they call it but if you describe the condition they will know.
Try to address this condition ASAP.
Good Luck

 

[JuiceMachine]

I use nothing less than 91 octane, but for the most part I use 94. I've done the decarbon proceedure and that didn't really help the problem. The sound is not a persistant sound. If I go over bumps when the pinging is happening the sound seems to move with the bump, what I mean is that the sound stops for that quick second. Kinda hard to describe. It almost definatly sounds like something is loose but not a heat shield. The pinging sounds way to solid for it to be a heat shield, like if you were to take 2 peices of metal and knocking them together. I think that I might actually have some time to jack it up this weekend and take a look. Would the rear mount cause something like that? I have burnished marks on the intake too and I thought that it was the front mount. I changed the front one a few weeks ago and the one that I took looked to be in good shape but I figured that I might as well put the new one in.
Any help would be very much appreciated... thanks everyone~! beer