For a couple of months I've noticed a problem with my engine under certain circumstances. 99% of the time, the engine runs flawlessly. When I punch it, the power is still fantastic. I can generally reproduce the problem by driving at about 55 mph on cruise and then going up an incline. At that speed, in sixth gear, my RPMs are at about 1500-1600. Under the extra load of the incline at low RPM, my engine rattle like crazy. I don't feel any loss of power. I can avoid the problem by dropping into fifth to raise the RPMs.

The truck is a 2011 5.0L with 140,000 miles on it.

I use a neighborhood mechanic, who I trust. I am not a fan of my local dealers. I took the truck to him today and he told me that I need a new timing chain,

I know nothing about variable timing. I came home and looked up the parts. They're not a terrible price. If I could be sure of the diagnosis, I'd have him do the replacement.

RockAuto has a kit including four chains, tensioners, guides, etc that looks like a good deal.

I wonder if I have a faulty knock sensor which isn't detecting the knock and adjusting timing accordingly. Shouldn't the knocking set a code? I also see that there are solenoids at work in this system. Solenoids can fail. Is it possible that something that simple could be causing my issue?

I believe that one way or another, this is something that I shouldn't ignore. I know the knocking isn't good for the motor. I need to make a decision quickly.

Any advice is greatly appreciated.

 

Have you ever cleaned your MAF sensor? I read somewhere that a dirty MAF sensor tends to have considerable lag, so you may be experiencing a lean condition as you start to lug up a hill in 6th gear. At least until the computer starts trimming fuel. I would start there, and maybe clean your TB while your at it before you start spending big $$$ chasing other problems.

 

Thanks, I've ordered a can of MAF cleaner from Amazon. I'll try anything before I spend that kind of cash.

I'll update in a few days.

 

I actually picked up a twin pack of cleaner from WalMart. I got a small can of MAF cleaner and a small can of throttle body cleaner for around $6.00.

Unfortunately, after using both products, the knock is still there. Looks like time for a timing chain after all. I'll baby it and run premium gas until I can get it done in a couple of weeks..

 

keep us posted

 

Before you spend all that money on a new timing chain, I don't think that's your problem. I had the exact same issue with my truck, but I have a intake and exhaust and it made the motor run a bit lean under the exact same conditions you describe. These 5.0's are tuned for efficiency, so they are right at the brink of running too lean 24/7 and knocking. I got a custom tune from Five Star Tuning and it completely took care of the issue. they sent me a performance 87 octane tune, but with the stock shifting pattern so it drives normally. The truck drives like stock, but with a little bit more power. No knock at all under the conditions that we experienced.

food for thought, before you spend all that money replacing your timing chain just to find out you still have the same issue.

 

First, I apologize for the delay. And second, thanks for the input. You were right. No timing chain needed. The story is pretty interesting from the last time I posted.

I decided that the truck probably needed spark plugs. I wasn't expecting it to cure the problem, but I knew it couldn't hurt. I changed out 7, no problem, but the eighth (front left cylinder) gave me trouble. I couldn't get a spark plug socket on it. Thank God it was in an easy location. I borrowed a borescope from work and took a look. It turned out that the last time I did plugs, I left behind something I shouldn't have. The rubber keeper from inside the socket had stayed behind on that plug. After all the heat it was pretty hard. I needed to break it apart with a long screwdriver and then blow it out with compressed air. After that, the socket went on fine and the plug came out easily.

The plug was pretty carboned up. It looks like with the rubber keeper in the way, the coil boot couldn't make proper contact with the plug. It wasn't enough to notice under most conditions, but under load, it showed up as knock.

I changed the last plug and the problem was already 50% solved. I ran a can of BG 44K Fuel System Cleaner through it and the problem was gone after one tank.

Lesson learned...I bought a magnetic plug socket. Great investment.

I picked up my new '18 shortly after, but the truck now belongs to my son who says it's running perfectly.

 

I've got a similar problem but since you identified the problem on the (front left cylinder) I wounder why you did not get a PO301 code. Did you hooked up an ODBII code reader and if so, were they any codes in it?

Note. Although the engine soon on my truck did not light up, I hooked up a code reader and there is a PO300 (random misfire) in the system. I erased it and after trying new high octane (94) and Octane additif, the code came back.

 

I did connect an OBD2 reader and never had any DTCs. That didn't make sense to me either.

 

Thanks,

Mine's got only 105000km on it (65000 miles) and the owner manual recommend to change the plugs at 160000km (100000 miles) but I guess I won't wait and hope it will solved the problem like it did on yours.

Thanks again for sharing the experienced/knowledge

Denis