I bought used 4.2l v6 2005 F-150 XL a month ago.
I noticed a knocking noise on the engine when accelerate just a little bid.
Anyone knows what is it?

 

if its anything like the 5.4L's, its the fuel injectors. i haveent heard about this problem on the V6's but its possible

 

It's like metal to metal knocking noise!
Injector? Interesting!

 

id get it checked out knockings never good

 

I have a similar tick/knock noise, dealer tried a cam phaser, didn't work, now they say the noise is from the lower half of the engine, and suggest a used motor. Ford customer service not very helpful, waiting for a week now for their response. My f150 is a 2006 with 38K.

 

A 2006 w/38000 miles is still well under warranty. I would tell the dealer to find it and fix it.

 

yeah i agree with madpirahna its under warrenty unless you personally upgraded the engine to a point where they wont pay for it.... a tick knock could be anything you guys it might be a tooth off of timing a froze piston ring worn valve guides or pistons have fun figuring this one out

 

The new car warranty is 3 yrs/36,000 miles. I have 38,000 miles and is 10 months over the 3 year new car warranty. This was confirmed by Ford customer service who denied assistance, and is pending with a supervisor for over a week.

 

thats so dumb, these cars and trucks last so long these days without major things going wrong. I'm going with 183000 and replaced spark plugs, and trani filter ha theyll last forever..... go full synthetic!!

 

had one of those v6 with same problem, it spun the rod bearing on #3 cyl. my fix was a carb 302 haha runs like a champ now