Hi Guys and Gals,


Been a while since I've posted. I guess the only time I post is if I'm having issues.

Anyway, my new problem is the truck started throwing "lean bank 1" condition code, and rough idling 2 mos ago. Took it to a repair shop and they incorrectly determined it was faulty 02 sensor. I took it back and they determined it was carbon build up and something called a carbon flush. That did smooth out the idle and no codes for 750 miles (truck seems to be running well).

But now when I cold start the truck, it feels and sounds like there is "hard" knock at start up. To my mechanically challenged ears it feels like a rod knock. It doesn't happen every time and only on the first start of the day.

I'm wondering if there isn't possibly some loose carbon deposit in a cylinder or if it's something else.

Anybody have an opinion or and idea?

Oh yeah, the truck is an '04 Lariat SCREW 5.4L with 98k miles with new plugs installed at 95k.

Thanks in Advance,
Jay

 

What brand is the oil filter and what weight oil are you using?

 

Sorry it takes me so long to reply, the coming holidays have had me busier than usual. the oil is pennzoil 5w20 and fram filter. I changed my oil but I don't remember if I changed it right before or right after the power flush. I'm thinking I'll go ahead and change it again.

 

Get RID of that Fram filter. The knock you are hearing on startup is a dry start, caused by a faulty anti-drainback valve in Fram filters. Go to Wallyworld and buy Motorcraft oil and a Motorcraft filter.

 

x2 especially the Fram. only use motorcraft oil filters and really any name brand oil will do, i aslo recommend synthetic.

 

There are other good brands, but not Fram. The PRICE for Motorcraft oil and filters at Wallyworld can't be beat though. The Motorcraft semi-synthetic is as good as any "synthetic" except the real expensive PAO-based brands (think Amsoil......).

 

Okay, I had some doubt on that, been using fram for years and was ready to debate the issue, but looking around on the internet, I'm convinced you guys are right about fram, as usual. Went to Wallyworld and changed oil and filter to motorcraft. the oil is 5w20 conventional.

But I wonder if the damage is done, I'm still getting an occasional knock on first start of the day. It doesn't happen everytime and only on first start but I'm wondering if I've spun a rod/crank bearing. Truck is running fine and no codes and oil pressure is good.

Is there a way to determine this without tearing down motor?

 

sounds like cam phasers and or timing chain tensioner is bad..

 

it's not the cam phasers, i have that also but this isn't cam phasers and if the cam tensioner were was bad wouldn't i have some major misfiring?
This knock is only on initial start of the day, if it happens at all and so far hasn't been performance affecting

 

i would just keep on driving it till something(if anything) breaks. you should be good though.

 

Yea, I've decided the same thing. I haven't had the knock in several days now and it doesn't seem to be performance affecting so I'll just press on and see what happens.

Thanks to everyone for their input, it's greatly appreciated. I love this site and Merry Christmas to all