ok it was running great i went and put i gas now irs missfiring i put a code scanner on it and it said it was no7 i ran some b12 threw it thinking it maybe needed and injector cleaned but it didnt work,,, next step is plugs and wires got any more ideas? its a 97 with 4.6 170k mi

 

Could be the injector. Check the misfire monitor history of misfire.

 

When was the last time the plugs and wires were changed?

 

plugs and wires both about 40k ago

 

It could be the gas that is the problem. I used to run 90 in my truck ('97 5.4L) and then decided to go back to 87 since it was cheaper and the recommended mixture. But it started to misfire and lost power. I need to replace my COP's because they haven't been changed since I bought the truck but apparently dirty fuel is an engine killer also.

 

The windings routing to #7 are most likely compromised - you need a pack - I would replace them both - best tune up you can give a 97..

 

I have the same truck 97 f-150 with the 4.6L and two weeks ago it started running rough and the the check engine light came on and i was like great it cant be the spark plug because i just replaced them 8000 miles ago so i was thinking it was something worse but all it was, was a spark plug.

 

What plugs are you using JRC ?

 

i took it to the mechanic and hes my dads best friend and he said the plugs and wires and the injector is good then he said he checked the compression and that it had none so looks like aim going to get a rebuild,,, i have been using about a qt of oil a month,

 

It had none?

 

he said that it had low compression

 

Oh , okay - I'de put a coil pack in her so you can get back to using all 8 of your cylinders before you blow the cats and cost yourslf more money..

I'de put a coil pack in her before your PCM goes into limp mode shuting down most of your injectors in an effort to save your cats, because you keep dumping raw fuel down #7 without fixing the problem..

At least unplug #7 injector if you don't wanna fix it..

 

I quart of oil a month isn't bad , unless you don't drive it..

 

well its kinda to late for me to do anything i really dont have time to woek on it myself i work all the time, so i am figuring i have 2k in it now and if i put 2 to 3k in it then i still have a good deal on my truck