Hey guys,

So, I don't typically like to post about something without doing my best to research as much as I can about it, but so far everything I've found through Google and YouTube don't seem to be what my rattle sounds like or have the same symptoms I'm experiencing. With that said, it's a 2002 4.2L automatic and it has a very distinctive rattle between 1000-1100 rpm. It's not the catalytic converter rattle (I have that problem too, more annoying than anything) it does it in every gear, park, or neutral, it doesn't matter as long as the rpm is in that 1000-1100 range its rattling. I'm not sure if my truck has the cam phaser set up in it or not because everything I've found online relating to that issue is always relating to a 4.6L or the 5.4L engines. When I'm driving the truck it sounds like it could possibly be from the transmission, not sure as I haven't had anyone available to help me hold the rpm while I crawl around trying to track it down. It's definitely noticable when my windows are down and I hear it bouncing off the traffic. Not sure if it's an urgent mechanical issue or just another annoying rattle to add to the cat rattle? Any and all help, thoughts, and ideas are appreciated!

Should also mention, oil change was done about 3 months ago. Last weekend I did some much needed cleaning of the throttle body and IAC valve (removed them both and cleaned them with carb spray, changed all spark plugs from the ngk ones that were in the truck when I bought it in 2013 to the motorcraft SP-504's all gapped at .054", cleaned the K&N filter, replaced the fuel filter, added some injector cleaner to the fuel system, sea foam through the brake vacuum line (done before I changed the spark plugs just in case it fouled any) basically just an all around tune up. The rattle sound was there before and still remains after the tune up. Had to add a quart of oil, but saw no obvious leaks other than a build up of crud around the passenger side pcv hose into the valve cover. The transmission fluid was about 1/4 inch under the hash mark on the dipstick for the hot reading while the truck is running. Also, after the tune up ive noticed almost twice the fuel consumption i was getting. What used to only take 1/8 of a tank to get to work and back now takes 1/4 tank (no change in driving habits). Kinda stumped here.

Thanks in advance!
-Jason

 

I had the same thing on mine, it was the cat converter heat shield, not the cat itself.

4.2 doesn't have phasers.

 

Yeah, I have the cat heat shield rattle on mine in addition to this new "mystery rattle" though... the cat heat shield is a more metallic obnoxious sound while this new one is a bit more subtle, but still noticable. No exhaust leaks either...

 

No other ideas? I will try to get a video of it soon when I can get some one to help me hold the rpm at 1000-1100. As of today I noticed it got a lot louder at lower rpm now as well. Trans fluid is reading good on the stick, oil is topped off. It almost sounds like something is loose and hitting a moving part. I guess the closest sound I could compare it to would be like back in the day when kids would put a baseball card in their bicycle spokes...

 

RESOLVED! So, turns out that the loud bell like sound I was hearing was in fact the engine lift bracket on the passenger side. One of the longer header bolts had sheared and the whole bracket was only being held on by one bolt. Tapped it with my rubber mallet and it sounded like a damn tuning fork! The more recent rattle noise between 1000-1100 rpm, was the driver side catalytic converter heat sheild. Removed the heat sheild and the engine hoist bracket, already 99% better while driving down the road. Still have a slight rattle, no where near as bad, but it's coming from the passenger side cat heat sheild. I'll remove the passenger side one tomorrow. Thanks for the reply GLC. Sorry I doubted you! Lol, I thought for sure the engine lift bracket was the cat rattle, guess I was wrong!