My MPG has went from the usually 15 city to 13 and I decided to change he COPS to fix the problem. Job easier said than done however. Now I am happy to say that I was able to install the set of 8 with little problems. It just takes time..........like my whole afternoon or like 4 hours. I fired the truck up after changing out each COP to make sure all was well. After completing the job the truck ran rough as all get out and I was like aw man what the heck happened. I rechecked my work and on the last COP I did not reconnect the wire. Restarted the truck and all good. Hope my MPG go up accordingly cause I have checked everything else except the O2 sensors and they are next if this doesnt fix the problem. I got 78k on her and was not gonna wait till a COP left me in a rock and hard place. If you decide to change them yourself the 1/4 inch drive extentions are the best. Thats what the guy used when my plugs were changed. I might even attempt those next time. Global Automotive COPS

 

That's cool Yea, if you have those miles on the O2's - Just change the forward ones, the rears are fine .. That will really help you MPG'S , specially with a healthy ignition system.

If your TB and elbow have been cleaned up recently - that helps allot.

DON'T forget the MAF as well, that should be serviced and cleaned.

Fuel Filter , Air Filter..

All contribute to you vehicles over all economy..

Congrats

 

78k miles -when was the last time the frt 02's were changed

 

You got experience with the coil replacment and will get experience that they won't help your mileage.
Your into a change of season, cooler weather and more gas degradation.
Wait till summer then that 2 mpg might return.

 

CHANGING SPARK PLUGS ON A 5.4L V8
Tools you will need for this job are a 7mm, 10mm, 5/16", 5/8" deep and 5/8" spark plug sockets. You will also need 1/4" and 3/8" universal joints and various 1/4" and 3/8" extensions. Use anti-sieze.
PROCEDURES:
Always be sure to remove your negative battery terminal prior to doing any work on the truck! Do not over torque the spark plugs or the bolts attaching the coils to the head.
1.Using your 10mm and 5/16" sockets, remove your throttle body cover. This will give you better access to what you are working on.
2.Using your 5/16" socket, remove the two bolts attaching the fuel line to the head of the engine. Once sockets are removed and set aside, pry the fuel line CAREFULLY away from the fuel injectors. Use caution to prevent damage to the injectors and the o-rings around the injectors. Beware that some gas will spill out when you remove the lines.
3.Pry the fuel line up and out of the way as far as you can without bending or breaking the line.
4.The coil’s are mounted with 7mm bolts, in between the injectors. If you aren’t sure which is which, the injectors are orange and have blue o-rings, the coils are black and typically have yellow stickers on them. Depending on the location of the coil, you may find it easier to use a univeral joint or a series of extensions to loosen and remove the 7mm bolt. After loosening and removing the bolt, you can unplug the electrical connector from the coil, and pull the coil out of the head.
5.After removing the coil, you can begin work on removing the spark plug. I find it to be a good trick to use to blow some compressed air in the hole or vacuum the hole out, to loosen any trapped dirt and prevent it from dropping into the engine.
6.Because the spark plug sits so recessed in the head, it is a good idea to attach a 6" or 9" extension to your spark plug socket. You may need more extensions so make sure you have enough prior to starting the project. It is also important to note that the spark plug does not sit perfectly vertical, it is at an angle, facing the rear of the truck. If used properly after removing the spark plug, the spark plug socket should hold on to the spark plug, allowing for easy removal.
7.Once you have removed the old spark plug, it is time to prep your new spark plug for installation. This involves gapping the spark plug and placing anti-sieze into the threads. To gap the spark plug, use a spark plug gap tool and slide the spark plug along the tool until you reach the desired gap measurement. For the F-150’s, the recommended spark plug gap is between .052 and .056 inches. You can also use a feeler gauge for a more precise measurement. You should place some anti-sieze on the threads to not only make it easier to remove next time you do the plug, but also helps keep the seal better then without anti-sieze, and prevents rust from forming in the head.
8.Once your spark plug is prepped, it can be installed. Unlike some spark plug jobs, reinstalling the spark plug is just as difficult as uninstalling it. Reason is you can’t just put the plug back in the spark plug socket and reinstall it. If you do so, the spark plug socket will grip on to the plug, and you won’t be able to get your socket out. The method I used was placing the spark plug in the spark plug socket slightly, but not into the bolt portion of the plug. By just placing the plug in deep enough so the socket won’t drop the plug, you can get the threading started, but remove the tool after a few turns with the socket. After starting the threading with the spark plug socket, switch to the standard 5/8" deep socket and torque down. Because the standard socket won’t grip on to the spark plug, you will be able to pull it away from the spark plug after tightening it down.
9.After the plug is installed and tightened down, reinstall the coil, reconnect the electrical connector for the plug, and reinstall the 7mm bolt. Repeat procedure for the following plugs.
10.Some plugs you will find are easier to replace then others. Use several extensions with a universal joint to safely remove the rear spark plug.
A variety of extensions and universal joints may be needed to access the rear most spark plug.
11.Once all spark plugs on one side have been replaced and all coils are bolted down, you will need to reinstall the fuel line. To do so, carefully place the fuel line into position over the fuel injectors and snap over the injector o-ring. Secure with 5/16" bolts that were removed previously, and visually inspect for tightness.
12.Repeat the same process for the spark plugs on the other side. Once completed, give yourself a good pat on the back, knowing that you just saved yourself about $250 in labor!

 

A few notes: The socket size for the fuel rail bolts is an 8mm. The spark plugs face forward on the driver side and rearward on the passenger side. If you work on a cold engine and or use a quality spark plug socket they will not stick to the plug. A bit of engine oil on the Injector O rings help them slide back into place a lot easier and can help prevent tearing them.

JMC

 

It still sounds like a real fun job.

 

My MPG were lower than normal in this past summer also. I know of the winter MPG drop but the summer got me searching for answers. No I have not changed the O2s yet but they will be next depending on my outcome.