Help ! 04 SD ext cab 5.4L Gas ! I have a mis-fire at low RPMs ! Autozone said it kicked out code P0316 Crank Position Sensor ( CPS ) but the CEL was not on ! So I replaced it and Still has the same problem. I checked the coil packs there good according to the autozone diagram "how to" ! I also pulled each wire 2 check the old shade tree way to see if I could tell that way. Now the CEL is on ANY IDEAS would be greatly appricated ! Thanks dave !

 

How many miles are on it? Plugs or coils ever been changed? What you are describing sounds like a bad coil. I have had 4 coils go bad between my van and truck and none of them caused the CEL to come on.

 

I can think of a few ideas.

How many miles are on the spark plugs? Are they all tight?

Perhaps it could be a camshaft position sensor misdiagnosed by the computer. I imagine they would both be related in some way.

Maybe the timing chain has stretched causing the sensors to misalign.

I just had a problem similar to this on my finacee's Grand Vitara. Her was a gummed up EGR valve and it threw a code for low flow to EGR. I removed the valve and cleaned it with carb cleaner and a wire brush. I also changed the spark plugs, poured a can of Sea Foam in gas and a can of spray Sea Foam through the throttle body. It now runs great and smooth as can be. The EGR was the true problem though.

i haven't had any problems like this on my 5.4L, but these are the ideas that come to mind.

 

A bad coil was my first thought as well. Same thing happened to my streetbike a few years ago...
The coil would test fine, and within spec...but that doesn't mean much to them.

 

Did they read the pending codes or just the codes in memory?

 

You can spend hundreds of dollars on parts guessing what is wrong or you can have it checked by someone who has the equipment and knowledge to diagnose the problem correctly. Autozone does NOT qualify. The choice is yours. If you must guess, a good tune up including plugs, fuel filter, air filter, and pcv valve would be a good start. Also do a GOOD look at ALL vacuum lines. And, clean the MAF sensor.

 

Thanks to All who responded with Ideas of help & Advice Guy's ! The Truck is an 04 F250 Superduty FX4 Package. 5.4L with 142K miles. Not sure if the plugs or wires have ever been changed due to I have only had this truck 1 yr ! I took it on my Elk hunt pulling my 23ft 5th wheel trailer and it started running rough at low RPM's on the way back. I Agree with you DavdB I don't have the time or $$ for that matter to play the guessing game on whats next so I'm going to put in the shop ASAP and let someone tell me whats wrong with it. I check back with the results !

 

*** UPDATE**** Truck is going in the shop tomorrow at lunch ! I will post the results and the fix when I get it back !

 

Ok I got my truck back yesterday ! They put new plugs in and replaced the #4 coil runs better but not right! So they did a compression test on the #4 cylinder only15 psi Because it was my dumba$$ that caused this by pushing the truck to the limit on the towing capacity ! A few words of advice to ALL out there..... Respect and adhere to the MFG spec.'s on the GVWR towing & hauling ! infact.... don't get close to the max. to costly and to risky ! $2000 for a rebuilt or certified used motor !

 

Did they say if the compression issue was bad piston rings or cylinder head related?

Although $2K is a lot of money, that is not as high as I expected. Especially if its installed for that price.

If they are going to swap motors for you, might I suggest you have them put headers on while the engine is out or at lease replace all the manifold bolts ARP studs or something of higher quality. That will be a big time saver in the future. Also check the oil dipstick. Mine broke off at the header and it is apparently a nightmare to change. Both relatively cheap parts that are way easier to handle with the engine out of the truck

 

Hey WizKid,
They told me they believe its a head issue. I have another cylinder that was running low as well. The shop told me that they would not know for sure until they tore it down. They told which ever way I wanted to go wether that be I rebuild the motor thats in it or get a certified eng. it would be around $2k to fix it. I had them stop working on it so I could think about the options. I did some research on line and found several web sites with used certified motor's with free shipping and 3 year warranty's ! There are 2 that I am looking at. 1 has only 69K miles on it & the other has 75K. Here's something that maybe the best news of all ! I have been working with my insurance comp. and I might be covered on this. Because I caused this damage by overloading the truck's GVWR it was not the trucks fault it was mine. So the Insur. opened a claim & I have an adjuster coming out Thursday to verify it with the shop that it was caused by me over loading the truck all I will have to pay is the $500 deductible.

 

While I disagree with the cause of the problem, it would be nice if insurance covered it for you.

 

That would be nice if it is covered, but I think it would be worth asking how it will affect the price of your insurance since I believe you would be at fault technically. I suppose there is a chance it would cost you more than just paying to replace the engine.

 

Phillips91
Thanks I hope so too. Why do disagree ? I'm going off of what happen when it happen & what the shop told me ? I'm open to suggestions on to what the Cause might have been ? I certainly don't want to go thru this again. I'm curious as to what you may think it was caused by. I just had the emissions & inspection done at the 1st of Oct. no signs of trouble at all ?

WhizKid, Thanks I'm hoping ! Yes I understand what your saying and I will be asking how this is going to effect my premiums and payments after if its covered.

The one thing that I know I will be doing for sure is upgrading to a Diesel ! Kinda sucks tho because like I said I have only had the truck for a 1 yr. and have put a leveling kit & new tires and misc. items have been added to to the truck and I love the truck it just cant do what I wanted it or need it to do.

 

I don't put much stock in the factory tow ratings as they are just a number to help them sell trucks. The 5.4 in the 250 was only rated to tow about 9,000 lbs, but when the half ton competitors raised their ratings ford somehow managed to get the tow ratings for the 150 with the same 5.4 up to about 11,000 lbs just so they could claim beat in class towing. Same engine, weaker frame, brakes, axles, etc, but capable of towing more weight? Plenty of guys with 5.4's on here tow 10-12k lbs with no issues at all, myself included.

How you drive and maintain a vehicle is the biggest key to getting it to last. Run it wide open and abuse it everyday, then it's not going to last no matter how little or how much weight is behind it. I exceed the factory rating by a lot, but I take it easy pulling out, don't treat every stop light like a drag race, etc, and have no doubts I will get a full life out of mine.