I,ve had my 2004 Endeavor for about 4 months now. It started making this wierd noise about a month ago. It sounds like something might be loose but I cant find anything. I had my boyfriend get under it and he finds nothing either. I thought that it might have been the engine pinging because I was unaware that it only takes premium fuel and i had been putting regular in it. So I tried fuel injector cleaner and premium gas. It made no difference. The noise is only when I have my foot on the gas pedal. As soon as i take my foot off the noise stops. It seems to be getting worse and worse as time goes on. Any suggestions?

 

Is it possible to get a recording of the noise?

 

it sounds like a rattling heat sheild or something along those lines.

 

Did you check for any loose heat shields and get a hammer and tap on the cat and see if the honey combs inside are damaged.

 

I'm sure this is not the answer but I was very impressed with the decreased engine noise when I switched to a full synthetic oil.

 

it is a loose heat shield on the exhaust manifold mine had the same issue until it fell off lol

 

the endeavor has a sheild next to the oil filter, it is common to bend the sheild back when changing the oil filter. this causes the drive belt to now rub on the sheild making a noise that is hard to identify.

 

what causes the engine to ping??

 

Engine running lean.

 

The sound is probably because you are using regular fuel...mine does the same thing. Next time you need to fill up use premium to see if the noise goes away.