Engine Ratttle @ 2250rpm

[NORDFORD]

2007 explorer 4.6 4x4

After the car is at running temp, and cruising at about 30-35mph, when I step on the pedal lightly to accelerate to about 40, I get a rattle that sounds like somebody shaking a paint can. If I can hold the pedal and keep the vehicel at 2250-2500 rpm's it stays there the whole time. If I get on it - no rattle. Only when lightly accelerating. However, it does not do it all of the time. Seems like when it is warm or hot out, above 80 is when it is worse. Once I hit 3000rpms, rattle gone.

It won't do it at the dealer, I even took a tech on a drive. Any ideas what could be happening?

 

[Old As Dirt]

The "paint can" sound is typical of preigniton. In the old days, if the timing was set too high, you would get this sound. All that was required was a timing wrench and a counter clockwise movement of the distributor. No more. You could try a tankful of high octane gas and if that corrects the problem, this is the cause. Rememdy? Maybe a computer reprogram?

 

[shaker1]

How many miles on the engine? The dealer will probably want to give it a carbon cleaning with no guarantee it will solve the problem. Carbon build up on pistons and valves can create hot spots that "pre-ignite" the fuel causing pinging. Usually worse on hot days under load while accelerating from lower RPMs.

They do make kits for do-it-yourself carbon cleaning.

http://3mcollision.com/products/cle...urself-diy-fuel-system-tune-up-kit-08963.html

 

[EX-SV]

Bad tank of gas maybe?

 

[NORDFORD]

50k

50k on the explorer. Shaker1, you hit the nail on the head. Since it has cooled off, no pinging. I ran a can of BG 44k a couple weeks ago too. It seemed to help.

 

[shaker1]

Some folks feed a can of Seafoam through to try and eliminate carbon.

This explains the process:

http://www.seafoamsales.com/how-to-use-sea-foam-spray.html

Also, can't rule out a faulty pre cat O2 sensor, they determine the actual A/F ratio you run. Or a dirty MAF sensor. It can be sprayed to clean with a good quality electronics cleaner. Check your plugs and gap them to spec too. I would use Motorcraft plugs, if I replaced them, with a dab of anti-seize on the threads.

 

[SpartanTS]

Had this issue on my 02 XLT 4.0L. It was the timing chain. It would rattle right around 2200 RPM.

Ran all the way to 210k miles tho with the rattle when we sold it a few years ago. I saw it a few months ago and it's still running.

 

[NORDFORD]

Problem fixed

Sorry it took so long to update this. Shaker1, you were correct. I ended up runing a couple cans of sea foam through the tank. Then a couple days after that I used the sea foam spray on my intake. When I took off on the "aggressive" drive per the sea foam directions, I thought I really messed something up. The knocking was worse! The sea foam must have broke more carbon loose. After about a block of knocking, I got a large white cloud of smoke from the exhaust, knock went away, and it has been smooth sailing since.

I may have my mechanic "fog" the fuel system anyway, just to be sure all of it got cleaned out.

Thanks for all of the help and replies! I'm not on here as often as I used to be, but this is a great forum!