How to find number7 spark plug

If there is no miss fire it could be piston ring or valve stem seal fault , if there is a miss fire check for faulty spark plug or high tension cable .

Did you change the spark plugs also ? Could have a head gasket leak between 5 an 7 ! Could have bad fuel injectors , clogged ! What about the speed sensor , you have a DTC stored in memory ,have check engine light on ? Need you to explain this a little better , misfire along with the speed sensor ! What about speed sensor ? You could have a vacuum leak affecting those two cylinders !

call the manufacturer and see if they can send you the replacement spring

miss fire can be a number of things weak spark plug damaged lead, faulty knock sensor or a problem with the injector.. clean the spark plugs check them for changes between them. there should be no real difference on them but black soot etc is a chance its over ritch. water getting in to the spark plug or a damaged rubber seal on the plug connector can also cause this problem so would check for this to. would say its the spark plug area my self.

the firing order is 1 8 4 3 6 5 7 2 It cant be in the wrong place unless someone moved it. the drivers side is 1 3 5 7

Number 3 is the 3rd plug back on the passenger side. Coils are notorious for going bad, I would recommend replacing the spark plugs, while you are there. Use Auto Lite, or Motorcraft Platinum Spark plugs only.

What size engine? Check the gap on the plugs as well. "pregapped" is not always right

Hi there;
I have run into an issue with these engines miss-fireing on #3 before.
You may want to have you tech check the miss-fire count for #3 & #7 on his/her scanner, THe distributor cap on these engines is made so the spark for #3 crosses over the path of #7 & they sometimes mix & become one. What happens then is they may be fooled by a spark coming through the wire if on a test lead but won't send the spark to the cylinder. The spark always goes to the easieat place so when cyl.#3 is ready to fire it is easier for the spark to go to #7 & vice-versa, So you tech will see a constant miss-fire on #3 & an intermitant missfire on #7. they can ceck the cap by pulling #3 plug wire off the distributor cap while the truck is running & there will be no spark, if he puts #3 back on & pulls #7 off there will be no spark there. the computor will only set a #3 miss-fire code because that is the cylinder that miss-fires the most.
If they find that is O/K you will want to have them do a compression test. If they find the compression is conciderably lower on cylinder #3 than the rest the camshaft theory is plausable.
The next step will cost you some money but it will tell you if you have an injector issue. You will have to pay you tech about 3.0 hrs to do this & you can just have them replace the #3 injector & hope it works. But they are around $200.00 rebulit so thats alot of money to throw at a hope. You'll need to get them to swap the #3 injector with the injector from one of the other cylinders then run the engine. if the miss-fire moves to the other cylinder you know you have an injector issue.

I hope this helps, Good luck, please let me know how you make out.
Farrout!

If this is a truck with The coil on Plug setup, I would suggest replacing the #7 ignition coil and the plug.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jonathan_3a3c556b4b17d1d2