I have been trying to figure this one out for my boss. She has a 1997 F-150 4x4, 4.6L Triton v8. She told me to check it out cuz it was clatering and oinging under load. I started it up, it idled perfect and drove really nice. I got out on the road and in 4th gear at 1500 RPMs at 1/3 throttle up hill it was fine until I pushed it down a little more. It sounded like a diesel engine. I got it up to and over 2200 RPMs and it was better but I had eased off the gas (meaning it wasnt to the floor anymore) and it sounded fine. I think it is just because it was too low an RPM to be going up hill and punch it. She had had the computer replaced, plugs, wires, injectors professionally cleaned at the dealer, new exhaust and blah blah blah and she still is upset with that sound. I honestly think it is runnig fine, but does anyone have any suggestions to look for under the hood? Anything I may have overlooked? I think there is no problem, but then again, my gool ole 302 could pull up that hill 1500 RPM in 5th and never make a whimper. Anyone?????

Thanks
Chris

 

I would suggest cleaning the MAF. If it is dirty, it will not correctly measue airflow into the engine and cause it to run lean.
Jimmy

 

Because of the gearing these trucks have, carbon build up is common in stop and go driving.

How many miles per trip?
4.6 are not big torque builders and trucks are a tank.

Is he expecting to much?? Driving in 4th up a hill??

My truck likes 3rd & 2nd most of the time.

We have to run 91 or better since we bought the truck, dealers fix for the ping is computer re-flash (read retard the timing) which kills the power.
Taking the truck for a 50 mile drive once a week makes a big difference.

My 2 cents

 

Trying burning some higher octane gas, a 92' model I have sounds like a small diesel if i try to run 87, put in 93 and it runs smooth.

Also, I'm a firm believer in Slick 50

 

I have a 97 4.6 4x4 with same type problem. I have taken it to Ford three times in the last two months and everytime they say it is a MAF sensor bad. That has been $300 a pop everytime. But this still has not fixed the problem. Had wires and plugs changed and a scan done and it came up with no codes. The wires and plugs have made it better but when you really have to get on it, it sarts a sound like spark knocking. Other people have told me to just run higer octane gas, but to me that means something has got to be wrong. Someone else mentioned carbon build up. I have run about ten bottles of fuel injector cleaner through it and should that have not helped that? And I also have been told to replace the knock sensor. An help or ideas would be greatly appreciated.

 

I've got the same problem in my truck when I try to go up hills in 4th or 5th gear. Most of the time its a result of a short shift into the higher gear. If I keep my revs up before going into 4th or 5th, I don't hear much pinging. Higher octane fuel helps out as well. I live at a higher altitude, and during the summer when its really hot, it really kicks up the pinging (I usually run 87 in the winter and 89 or 91 in the summer). This is a result of what pilots refer to as density altitude. The combination of higher altitude and higher temperature creates a condition where the density of the air doesn't allow the engine to produce the rated horsepower for a certain RPM. Normally its not an issue for cars since they don't experience severe changes in altitudes. But for me, I can be at sea level when I start and 30 minutes later be at 4000 feet. Add in the effects of temperature, and the density of the air equals what it would at 6000 feet. That means that at the same RPM a certain gear may not work as well as it would at sea level. You basically have to run a higher RPM instead of shifting at a normal RPM to create the same torque. My terminology here may not pass an engineering exam, but the idea holds I think.

 

I have that engine in 2001 S'crew and it doesn't like BP gas. Doesn't care for Shell or Texaco either, but its not as bad. Have her try and switch brands, runnng three tanks of each to see if problem goes away.

 

From what I have read in other posts you might want to check and see if the EGR ports are plugged up with carbon.

 

Put some high octane gas in it as already mentioned and get it hot .It may be also a problem with the computer or sensor not properly retarding the timing at WOT ect as well but that should give a code and check engine light. I used to pull the probe out on my Grand National and get a check engine light. Carbon can and will build up in the heads and start to glow causing pre ignition/detonation and even raise compression on motors that are frequently shut down before reaching operating temp.A good indicator of this is a snotty/ milky looking oil filler cap and neck. Never shut a cold motor down. If it is detonation that pinging can pop holes especially in hypertect (SPELLING) pistons.