I have a 1999 F-350. I bought the truck 1.5 years ago used. It has run great. Lately the fuel milage has decreased and now I hav a loud rapping noise that sounds like it is comming from the top of the engine and it is running rough. I replace the idler pulleys and some of the noise went away. Does someone live close to Augusta, GA that can help me find out what is wrong. This started after Jiffy lube changed the oil. Oil levels are fine. The truck has 130,000 miles on it Hope this won't be to expensive to fix money is tight.

 

Loud rapping huh. Does it sound like the injectors have gotten louder? You may want to try and change the oil again yourself and use 15w-40 or 5w-40 rotella. I've heard stories of jiffy putting the wrong weight oil in engines before. Other then hearing the rapping noise, its hard to say what it could be. Maybe grab a piece of tubing or hose you may have lying around, hold to your ear and the engine while running to see if you can pin point where it may be heard the loudest. Does the engine seem sluggish when running? like its lost power?

 

The "rapping" sound could be the tensioner starting to go bad. Mine was pretty loud when it was on it way out. I also saw a lot of deflection in the belt between the power steering pump and the alternator that went away with the new one. For the rough idle I would try unplugging your icp sensor and see if that helps when started. Are the filters all in good shape? Maybe jiffy lube knock something loose in the engine. Here is a pic of the engine labeled if you don't know where the icp sensor is. labeledtopview1a.jpg picture by galexander - Photobucket

 

Yes it seems sluggish. I watched Jiffy Lube put in Rotella T15w-40 Could the injector pump need bleeding I don't know if they did anything else up under the truck. They tried to get me to replace the fuel filter but it was done last service 3000 miles ago. Could a blown boot cause this? I have 2 that are sooted up and I don't get over 15lbs boost.

 

You also might have a rocker arm coming loose and the pushrod is tapping.

 

This part really concerns me. To answer your other question, no there is nothing to bleed. The wrong oil, wrong oil pressure on the high side, foaming oil, etc. can cause injector knock, which sounds like a tapping noise that is most noticeable at idle. Does the truck sound better when you start it up cold first thing in the morning, but seem to be worse after the engine is fully warmed up?

I know you said you watched them put in Rotella 15w-40. Did you watch them remove the seal under each cap (assuming gallon jugs)? Did they put 15 quarts of oil in?

There's a chance you're either really low on oil or they just filled empty Rotella jugs with the stuff the pump into the cars because they do not know enough about HEUI systems to understand it could cause a problem like that.

My vote is to check the oil level first, then if it's full, go ahead and change the oil to see if that fixes it.

 

I know you said you watched them put in Rotella 15w-40. Did you watch them remove the seal under each cap (assuming gallon jugs)? Did they put 15 quarts of oil in?

Oil level is fine. I did not see them remove any seals. They just opened the jugs and poored them in. I have noticed that I have a lot of grey smoke comming out of the exhaust all of a sudden. The truck sounds fine until it has run a short while. Then the noise starts and it runs rough. The noise goes away for the most part when I give it some fuel. The engine still has a vibration in it though that can be felt in the steering wheel.

 

Wow if it all started with an oil change I would get that oil changed again pronto.

 

I changed the oil this AM. I am a pastor not a wrench monkey. Oil changes are at the limit of what I can do. I also found and drained the fuel bowl. The truck runs very quiet now but still idles rough. Was hoping some one close by had a scanner and new how to use it. Both Advance auto and Auto Zone told me thier scanners won't work on my truck The local ford stealer wants me to leave it with them and they will call me in 3 or 4 days as they are backed up for work They want 100 dollars just to hook up the computer.

 

Don't let your day job influence your attitude or confidence when you pop the hood. Many of the people here were just as intimidated as you sound when they first came here in regards to their own mechanical ability. We'll be more than happy to walk you through anything you may want to do, or can just offer advise when dealing with a real mechanic.

First off, there may be someone close by. We'll just have to wait for more GA members to see this. You might also place a thread down in your local state chapter section to increase the viewership by locals.

Next, I'd skip the dealer if I were you. If you're forced to get professional help, I'd find a local independently owned diesel shop that can look at it quicker and for less money. Many school buses and ambulances have or had the 7.3 motor in them. If you know anyone in one of those fields, ask them where they get their diesels fixed. You'll probably find a good diesel tech that way.

So are all the noises and concerns gone now other than a slightly rough idle? How much better do you think the oil change made it if you were to guess at a percentage improvement? How much have you driven it since your oil change?

So far it sounds like you're better at changing oil than Jiffy Lube.

 

If tapping or noise goes silent when in decel, would that rule this out?

 

I have changed the oil, drained and cleaned the fuel bowl, changed the fuel filter. Noticed this AM after changing the fuel filter yesterday and driving it 30 miles it ran smooth till it warmed up then it idled rough and was rough at about 1700 Rpm. Some one suggested I pull the ICP sensor. When I did the truck ran worse. I found some one who had a code scanner and went over there, The truck has no codes set. everything was fine according to the scanner. HELP!!!

 

Most code readers, including the free scans from the parts store, don't work on our engines since they were designed as medium duty engines, not as an OBDII compliant car engine. If you unplugged the ICP with the truck running, then there is a code stored and your friends scanner just can't see it.

When you unplugged the ICP sensor, the engine idle got worse? Also, just to clarify things, are all the loud noises gone and we're just dealing with a rough idle when warm issue now?

 

Engine idle got worse with the ICP unplugged and the engine now runs rough when warm. The loud noises are gone.

 

So apparently Jiffy Lube did not fill your truck with the proper oil since the original problem is fixed. I'd avoid them in the future.

For your new issue, the engine isn't supposed to idle worse when the ICP is unplugged. Does it do this both hot and cold, or just after it's warmed up? I'm wondering if you don't have an o-ring problem on the IPR. Let's see what others have to say.