Hello everyone. I am new to the forum and absolutely love what I have found so far...great information here. I know that this issue has been beaten to death and I do appologize for bringing it up again. But, I have searched and searched and cannot seem to find the answer. Please forgive me if it is already out there and I just cannot locate it.

Anyway, I have a slight miss in one of my 8 cylinders (not sure which one as I am waiting for the dealer to tell me that bit of information). I have taken it to two different Ford dealers and am getting conflicting information. Both say yes, COP is bad and needs replaced, but when I asked about the part number, that's where they disagree. One dealer says I need DG508 and the other dealer says I need DG521??? I do not think these two parts are interchangeable, but maybe the DG521 is a new part number and replaced the DG508?

I have asked them to check the boots to make sure that there isn't a cracked one that maybe arcing and is causing the miss. No CEL codes thrown yet, but when I first step on the accelerator (mildly, moderately, or severe stomp) there is a delay in take off. I can feel the vehicle kind of sit there and then all of a sudden it takes off like a bolt of lightning. And, my gas mileage has gone to crap. I am currently getting about 11 mpg when I was previously getting 16-18 under the same driving conditions.

I have a 2009 XLT 4X4 Super-crew with the 3V 4.6L engine. If it helps any, the first 8 of the VIN is 1FTRW148xxxxxxxxx.

I am fairly handy and believe I can change the COP myself rather than pay an arm and a leg at the dealer. I have always done what I can when it comes to repair work, and changing out the COP seems fairly simple from the other posts I have read here, so if someone could help me figure out why I am being told two different part numbers (maybe they're the same thing, but I don't think they are) I would really appreciate it.

Thank you and, again, great forum with a wealth of inforamtion for a lifelong F150 lover!

 

From what I can find DG521 is the one you need. However, I've found both numbers for the 3v 4.6L. Check the color of the boots for sure, brown=DG521 black=DG508. DG508 has been around for years since it's the same COP that the 97-03 trucks use, so no number change.

http://www.fordparts.com/Commerce/Ca...WLK+LH7viyyDAr

 

I just checked O'Reilly's and Rock Auto for the 2009 4.6. They both say DG508. May have to pop the hood and see if you can read it off of one already installed. You could always call another dealer service department and see if they tell you the same thing. But if it's not throwing a CEL or SES, do you know which COP it is? Mine is much older, but it feels a bit like a miss, but it's actually my upstream oxygen sensor on the driver side. I plan to replace it before it actually codes. I just replaced the passenger side (bank 1 sensor 1)and it started the same way. Went on for several weeks before it coded. Ah well, the truck has new plugs because of that, so all is good.

ETA: I just reread your post. If it hasn't thrown a code, how does the stealership know it's a COP and not a plug? How many miles do you have on it? Not trying to be rude or anything, but a 2009 isn't very old to be having a COP issue. JMO

 

go to autozone, get your code read for free, buy a COP, change it in the parkin lot. easy as pie

 

Thank you all.

DragonWolf I completely agree. 2009 is failry new for it to be a COP issue, but that is what I have been told (I don't necessarily agree so I am hoping to get some insight here, which I have and in a great way). I have 52K miles on it. Purchased it used with 37K on it. It has alwasy been a bit sluggish compared to my previous F150s but it was the first 3V engine I had so I didn't think it was anything to be worried about until recently when the MPGs started going down.

Since my original post I have discovered that I have the COPs with the brown boot covers, so that, I believe, means that my engine has the DG521 part code. I believe, maybe incorrectly, that FoMoCo started using the DG521 COPs in their newer 3V V8 engines beginning with the 2009 model year, but I have nothing to back this up with.

I did also notice when I was looking at the boots to determine if they were the black ones or the brown ones, there is an awful lot of "old" dirt on top of and around the engine block. Seems a bit strange to me as I have never had this truck in the mud since I have owned it but I do recall that the previous owner lived in a remote area with dirt roads. I mention this only because I am wondering if it is possible that one of the boots may have a crack in it or a piece of dirt has worked its way under the boot and thus is the real cause for my hesitation/miss? I also know that with the COP you are not supposed to spray wash the engine for risk of getting water in the plugs. I'll use my air compressor to blow out the dirt that has collected.

I don't exactly trust the dealership and thus want to make sure that it is a COP...even if it is, the dealership will not be doing the work. I have kept reading and it seems pretty easy to do....unplug the COP, take the small bolt out, put di-electric grease on the new one, but the bolt back in, and re-connect the wire. 10 minute job that no doubt the dealership will charge at least an hours labor to do.

I cannot find the brown replacement boots at any local auto parts store. One has ordered them for me at a whopping $3.99 each. So for $32 I can try that first to see if it makes a difference. Thought I would start by pulling the boots and seeing if I can see any evidence of arcing or anything before I go and mess with the COPs. I really do not believe that it is a bad COP.

Thank you all for so much great advice. I'll post more after I get the new boots and pull the old ones off to see if I have found anything. May be after the weekend. The parts store that has ordered them for me said they may not arrive until Monday.

Thanks again.

 

sshupe - you probably have original plugs too. You can buy the Motorcraft plugs for way less than FoMoCo dealerships sell them. They are a pain to replace, especially #4, 7 and 8, but one may be out of gap. Possibly any one under a suspect boot or COP. If you get an aweful lot of blowoff when changing the boots, you may want to pull that plug and inspect it too.

 

i dont like how much you write

 

Thanks DragonWolf.

And, for what it's worth I'll try to write shorter posts.

 

I, for one, don't care how long the post is as long as I can understand it when I read it.

 

I'd much have a long well written post than pozt da tlk lik di$ & Du n0t m8ke cents.