Hey guys, I have a 97 F-150 with the 4.6. I have noticed that i have this loud chatter from the engine when i put a load on the motor. i really notice it when i accellerate fast and it shifts into 3rd gear i start to hear it, it happens when its in OD and i accellerate slow enough that the tranny doesnt down shift, and i hear it when i haul my boat and accellerate slowly. It most ly happens at speeds of 45 and higher. Could this be my lifters or valves chattering? Its really annoying to hear this, and im afraid of doing dammage to the motor. I really need to find out what this is. Its driving my nuts. Thank You Shawn

 

Well, it could be detonation which could be caused by a few different things. Low EGR flow clogged EGR passages, lean air/fuel mixture (dirty MAF or vacuum leak possibly PCV hose) or carbon build-up in the cylinders.
It could also be an exhaust leak at the manifold. Look for black soot and broken studs where it bolts to the head.

 

sounds like spark nock from cheap gas... dirty injectors possibly

 

I have been battling this same issue since I bought my truck last year. I have tried tons of fuel additives, with no real success. I have also replaced my plugs/wires and cleaned my MAF. All with invaluable instructions from the folks right here at FTE.

Recently, my shop suggested that I get a "fuel system cleaning". I am not familiar with this process. Does anyone have any experience with what the cleaning involves and how effective it might be?

The way they described it, they use a pressurized canister to deliver some chemicals that burn out any carbon deposits in the intake, throttle body and injectors. I have manually cleaned the throttle body even though I know you are not supposed to (it was pretty clean before I started), so I am not sure if this is what I need or not.

They said to expect the process to take about and hour and cost about $100. They also said to expect a little better HP & fuel efficiency following the treatment. I know from reading this forum that everybody and their brother promises improved fuel efficiency and more HP for everything from mods to additives. Is this just another empty promise?

I have had great experience with this shop, so I do not think they are trying to take me for a ride. They could have done that long ago if they were interested. I think they really believe this will help, but I do not want to spend $100 to find out that they are wrong.

Thanks, folks.

 

I sure don't intend for this to sound smart-alecky. Did you clean out the throttle body? Or the passageways in the manifold underneath the throttle body, where the EGR valve bolts onto?
That's where the carbon accumulates and plugs up the innards.

 

I notice the same thing when i burn cheap gas

 

banjopicker66, do worries on sounding smart-alecky. BTW, as a fellow SC boy (originally from Florence), you and I are about the only ones who would use smart aleck as an adverb.

Anyway, your point is well made. Actually, I do not remember exactly what I cleaned. I removed the whole throttle body and cleaned as much of the lower intake as I could get to. I also cleaned the IAC. I think I cleaned the ports that you are referring to. I think they are on the bottom of the throttle body. I seem to remember that they were not as gummed up as some of the stories that I had heard.

At any rate, is this the stuff that the "fuel system cleaning" is going to address? If so, then I might just pass on it. If the other items to be cleaned (injectors mainly) are worth the effort, I might just go for it.

I just don't want to throw $100 at something that a fuel additive will address, but so far, not fuel additive has made much of a difference.

Thanks, smart aleck.

 

Waaeel now, that's a right polite answer!
Seriously, I found I had to remove the "manifold" underneath the throttle body - I think. (I am in Charleston, WV right now on a business trip.) The passageways in question, are reight behind the EGR valve, so whatever part the EGR valve bolts to, that's what you have to remove and clean.
It isn't hard to work on, just a little time consuming. It is really pretty easy to do, and it isn't even as slow as molasses going uphill in the middle of winter. Figger 'bout 2 hours.

By the way, I lost my work down here. I have a job, but have to move to WA DC to stay with my company. Know any possibilities in my beloved Southland? SC would be best, but NC, TN GA and AL would be fine. I do computer network security and progam manager for such work.

And, Deo Vindice!