I have been throwing money at my truck. I am chasing my tail and need some help. I started with about 7 different codes and I am down to no codes now, but still haven't fixed the problem entirely. My F250 has 177,000 miles on it. My problems began with no power and a shutter on accelerating that was bad enough that I did not know if I could make it home. I was immediately sure that it was my catalytics, but I started with the fuel filter, then with spark plugs, and finally with new catalytics. All this work needed to be done anyway. I then had code P1404 left over so I (out of ignorance) replaced the EGR valve that may or may not have been needed. I then replaced the DPFE sensor. Everything that I have done has lessened my symptoms somewhat. I still have a hiccup, miss or hesitation at idle and can hear and feel the same when excelerating. I erased my computer codes so I wouldn't have anything for them to read at a shop if I took it in. There are no codes presently and the CEL has not come on. I just ordered new COPs off of Ebay to try that ( I did not change them with the plugs), but I am wondering if anyone has some other suggestions. Thanks to all. This forum has been a great find.

 

Could be a weak COP or a bad boot causing a misfire.

 

I am waiting for the COPs to get here in the mail. I went to replace the PCV valve tonight and found that the old one wasn't even in the valve cover hole. I put a new one in and it seemed to make little to no change to my problem. I will put the new COPs on when they arrive this week. Any other ideas please let me know. Thank you for your response LxMan1. Still no CEL or codes showing up.

 

Clean the MAF sensor and check for vacuum leaks. Also, check the fuel pressure when running, should be 28-30 at idle, 38-40 with key-on-engine-off, and 38-40 when under load.

I bet it's the MAF is dirty after so many miles

I know with my V10, it makes a noticable difference to clean it after only 20K miles or even less...

 

Thanks for the input Krewat. I just cleaned the MAF and it looked as if it needed it badly. First time that I have done that. I took mere minutes so I won't put that job off again. Unfortuneatly I still have the same problem although maybe somewhat diminished. I will go over the entire vacuum system looking for areas that I might have missed. I will have the fuel pressure checked for me as I do not have the tools or experience to check it.

I should have my COPs in by Thursday and will start to replace them. I am not looking forward to that job. Changing the plugs the first time took me forever. I hope that I learned enough to be a bit quicker this time.

Another tip for others is that I went to Ford to get the 90 degree adapter for the PCV line to the back of the throttle body and the parts guy could not find it. All he had was a entire PCV system for $43. He found another part number that worked nicely for the job though. It is a Ford Genuine Part #YS4Z-6A614-BA.

 

Did you get new boots with those COPs?

Apply a bead of dielectric grease around the top of the boot where it fits to the COP, and around the tip where it seals against the plug. I also put a bead around the seal area on the outside diameter of the boot where it seals to the head.

Changing the COPs isn't SO hard I put floor mats on top of the radiator and grill and just laid my 240 lbs gut on top and did it that way

 

I changed the plugs a month ago and replaced the boots and springs at that time. I was new to COPs and did not know to add the dielectric grease at that time so it probably good that I will be taking them off again. The new COPs should arrive Thurs or Fri. I will try to get time to get the job done this weekend. I hope that you are right and changing the COPs isn't too bad. I had cylinder 3 and 4 done for me last time but I think I can get them myself; now that I have found this site and learned a thing or two more about working on this motor. I still need to check the rest of the vacuum system and fuel pressure. Thank you for the follow-up advise. It is appreciated.

 

And definitely report back if you solve it

And if not? Well, come back anyway

 

Thank you for the help. Looks like the problem is fixed. My best guess is that most everything I did needed to be done (maybe not the EGR valve). I got the new COPs installed tonight and she is running like a champ. No missing, Plenty of Power, like a new truck again. I would mostly agree that replacing the COPs is not a big deal. I needed a 1/4 universal joint to make this easier. Number 7 was a pain without it and the fact that I have very large hands didn't help. Total job took me about 2 1/2 hours. I believe that I am going to take it out for a spin now. Thanks again for all of the help.

 

I don't know if anyone is checking this thread anymore but I have another question. I am now pulling a P0161 code after driving a few miles. From what I gather it is for the downstream O2 sensor on the passenger side. Can anyone confirm? Also I saw on another post that it could be the PCV elbow behind the Throttle Body, but I have anlready replaced that part. Is there anything else that could throw this code?

 

That's a heater circuit failure for the downstream passenger-side sensor... I think.

A PCV elbow would not do that. It's a wiring fault, or the heater in the O2 sensor went.

 

Today it is raining in Seattle and I don't feel like lying in the street (since I don't have a garage) so no work on the truck. I did see a few posts that peaked my interest though. Is it true that I am best to purchase only Ford O2 sensors and stay away from auto parts store brands? Does anyone have experience that they can weigh in on this one. I am for saving a buck where I can but not at the expense of doing the job right. Changing the sensor will be a breeze I just need to know if I am foolish to go to my neighborhood auto parts store for the part instead of making the drive to the nearest Ford dealership who is not open on weekends.

 

I've heard that the Bosch O2 sensors do not react as quickly as the Ford sensors. People have actually watched them with scan tools and saw the difference.

Maybe you can find Motorcraft brand sensors somewhere?

 

Hopefully this is my last of my uneducated questions. I got around to picking up an O2 sensor today and installed it. I did go with the Motorcraft after what Krewat said. The old Bosch sensor looked pretty clean as did the wires so I think that that is the one that I had replaced by a shop in March of this year. I started the truck up after changing the O2 sensor on the Passenger side after cat, which I hope is bank2 sensor2, and still have a Check Engine Light on. My question is two fold. Do I need to clear the codes or will it turn off after further diagnostics if the problem is fixed? and secondly, What is the likelyhood that it is a wiring problem and instead of an O2 sensor problem? Thanks again in advance for all of the solid help that I have received here.

 

You need to do a few drive cycles before it'll clear on it's own. Better to disconnect the battery overnight ...

Could be wiring, for sure...