Hey Guys,

My truck just rolled past 21000km a few days ago and while I was driving it last night on the highway doing right around 100km/h it threw a check engine light. Truck ran fine, and no apparent issues came about at that moment, everything seemed normal. What I did notice though was that when I came home and backed it onto the driveway I heard a noise from underneath the truck. Just like the title reads it was a fast paced clunking sound... it wasn't overly loud, but it was def noticeable.

So I tried searching it up last night and I got no answers, thought someone on the forum may have experienced this same issue. Has anyone had this before? Also I used to own an intrepid and if I cycled the ignition 3 times it would display the OBD code in the odometer. Do our trucks have that capability or can they only be read strictly by a scanner? Again I tried searching this but came up with nothing.

I'm taking her in to the dealer tomorrow to get it checked out, the things brand new, and I've been driving her easy lately so I'm clueless as to what it could be. I'm thinking it's coming from the accessory drive, but it was noticeable more to the rear of the engine and with the hood propped open I couldn't hear it from above, only through the wheel well.

Anyways I'll keep you all posted on what the dealer comes up with. Hopefully it's nothing too serious.

Thanks in advance,

 

Dude you have a warranty use it

 

That's the plan.

 

Just bought a 2011 4x4 with a 4L and it occasionally has a knocking noise coming from underneath too. It happens only once when starting out and cold. Have read complaints from others on this issue. I don't know what causes it, but with other 2011's having the same issue Ford will figure it out.

 

Mine does this too!! just started about 3 weeks ago. get back to me with the solution. its only when its cold, and when i feed it just a tad of gas while at idle in any gear. once it hits 1300rpms and up it stops....

 

To the best of my knowledge, that is the AC compressor cycling on...

 

No its nothing like the ac if its anything like mine. Its fast as heck and its definitely under the truck.

 

I have that sound too and only when its cold aswell, but like Fink132 said I'm pretty sure its the AC compressor. It makes a "thump" sound, and only does it once after which its fine.

To update you all on my truck... turns out that my catalytic converter is clogging up and needs to be replaced. The truck sounded sort of diesel like with the clunking it made (again only noticeable from underneath the truck) and it made a hissing sound when I got to about 2000rpm. All covered under warranty, only problem is the cat is on back order and wont be in for a week.

 

^^^Wow, its still fairly new and a converter failed. That would really bother me, and I would ask the service manager why this happened just for his opinion. From my experiences, the fastest way to kill a converter is from running too rich or putting leaded gas into it (if you even have that opportunity and without trying to find it for sale), but thanks to fuel injection and the high reliability that comes with it, cases of extreme running rich just don't seem to happen much anymore. Where I'm going with this, and why I'd want to hear their opinion of the cause of this (not that I'd automatically buy the answer, depends on what they say) is that I'd be wondering if the reason that caused this to happen is still there and will another converter fail down the road, and like, after warranty. FWIW, I have seen a few converters over my last 30 something years of working on cars that were actually bad to begin with, but it's sooooo rare.

*Is there any chance you buy gas from a station that also sells leaded gas, and for some reason, by accident or on purpose, they may be putting leaded in the unleaded tanks and selling it as unleaded? Also, when it's warm and you stand outside the vehicle, did you smell H2S (smells like rotten egg)? What code did it throw? The ticking you heard was heat causing the metal to expand/contract, the hiss is from an exhaust restriction, caused by the plugging of the converter.

 

I found it really odd aswell that the cat would fail so soon. When the repair is done I'll ask them what the exact code was and why (to their knowledge) it failed. Like you said, it could be a few things that led to such a quick demise.

The gas stations in my area all use unleaded gas. Now if the stations decide to possibly sell gas with lead on rare occasions is beyond me, but everytime I fill up at a pump it clearly says unleaded. I didn't notice a rotten egg smell from the exhaust either, although I was checking to make sure there was no blue or white smoke coming from the exhaust (I was hoping my motor wasn't burning oil or coolant) which there wasn't and did not pay much attention to the smell of it.

Thanks for the info!

 

Hey all,

So I got the truck back. All fixed under warranty, didn't have to pay a cent. So the code that the truck threw was P0430 (Catalyst System Efficiency Below Threshold (Bank 2)). The engine checked out, nothing fuel or ignition related according to ford so it was entirely related to the cat in the end. Basically as to why it was clogging up, they chalked it up to being defective.

Anyways, happy I have my truck back finally... drove a car around for that last few days, and it was more comfortable and faster, but it I was getting cut off consistently by other drivers, drove me nuts. Doesn't happen when I'm in the truck though!

 

Glad to see it was taken care of. The comments about leaded fuel, isn't it banned or something?

 

Hi All,

Mystery solved... Turns out the noise and slight vibration my truck makes at 1800 rpm on a cold start drive off is normal. It's caused by the ABS self-check.

 

you never know when someone puts some zip ties on your driveshaft lol... did that a few times to the upper ranking guys on my deployment.. Along with wiring up the horn to the brake pedal

 

Glad to hear that the sound is normal. I was about to take mine in. In does it,like a little clunking up front,every time when hitting second on a cold start. ABS cycle,hmmm.