Hello all. Replaced the spark plugs on my 02 4.6 about 2 weeks ago. Afterwards I had a slight miss which after reading many posts I believe it may be a cop. Maybe it was from me messing with them replacing my spark plugs. Anyways about a year ago my truck missed real bad from 1500 rpm to 2000 rpm but that went away the next day I turned my truck on. Which also leads me to believe cop. Also no CEL of course so it's like fishing in the dark. I have college soon so not much time to work on this. I was reading that some people say using the torque pro app they could read missfire. Will I be able to find this bad cop or whatever it may be when there is no CEL? thanks!

 

Did you gap the plugs before installing them?

Does it have a slight miss at idle? If so, unplug one coil pack at a time. If the idle gets worse then you know that one is good. Plug it back in and move to the next one. When you get to one that doesn't change the idle after unplugging it, that's your bad one.

Wayne

 

Yep I checked the gap on all of them. And no idle seems fine. It doesn't seem to happen all the time. But when it does its low in the rpm range and under load. I have the 5 speed btw so I can't really do the check at 45 mph when it shifts into overdrive. Would my best option be buying on cop and replacing one at a time and test driving or try this torque app?

 

Yea, we are sort of in the dark, since you don't offer up the parts you used. Plugs are definitely not all the same, these engines can be picky. I suggest that you detail your question without leaving anything out.

+1 on the Torque app for finding low grade misfires. Your on the right path there.

 

So far I have reseated all the cop and put dielectric grease on them. I've replaced the fuel filter (that thing was extremely clogged up) and cleaned the egr system and maf sensor. Maybe a vacuum leak ? Or should I check fuel pressure? Also just to make sure I used sp413 spark plugs as this is what I found online when entering my Vin number does this sound correct? Sorry if I'm all over the place been up since 430 and had way to much coffee

 

The spark plugs were motorcraft sp-413. Trucks a 2002 4.6 5 speed

 

Anyone familiar with mode $06 testing with a scanner. I tried reading an article about it but it was a little over my head ?

 

Fuel delivery first, - always. It's a bi-law. So yea, check for a weak pump.

That said, - sounds like a low grade misfire.

Easiest way is with the torque app. Not really for the mode 6 date , but the live data. W/real-time data, watch your phone for the misfire. That's the easiest way how you determine.

There's many in depth explanations about this, but that's the basics your after and it's a cheap set up.

 

Do you have access to a scanner thats capable of $06 data?

 

Alright well since it's a law I guess I have to find someone with the necessary equipment to check the fuel pump

But anyways. Just ordered a dongle off of amazon and should be here next wednesday! Thanks for the help!