I just experienced a sudden and continual COP like miss yesterday on my 98" F150 5.4L and had to drive quite a ways to get it home. The typical CEL light did not come on and my code reader has not registered a code yet, "No Codes". What the hell? Suggestions please.

I need it running right now for work. Having had several COP failures in the past, it exhibits the exact symptoms but no codes or light yet. I even leaned on the gas a few times to help trigger the CEL, but to no avail yet. babied it the rest of the way home. I have an extra new COP for such an occasion though. Yelp.....

 

shooting in the dark here since you didn't give a whole lot of information.

Is it when you are up in OD? like around 45-65MPH?

If so, I just had the same problem. It is a misfire. They don't throw codes all the time.

Fix that worked for me:
Coil Packs
Spark Plugs

A few hours of work and it ran amazing.

 

No, it's started missing going up a hill and at all RPM's and kept up even at idle.

Now that you mentioned it, COP failures in the past were present mostly in OD and got steadily worse.

 

It's a cop. It's not missing enough to throw a code for most scanners to pick up. Mine did the same thing after going through a mud hole that was a little too deep.

 

Yeah mine did the same. It eventually threw a code...but just replace them all...people frown upon getting cops on Amazon but I did for about 50 bucks and they have been running strong for about 4 months now...knock on wood..
Better than paying 45 per though

Like I said I did my spark plugs at the same time. A few of the packs are a trouble to get to so you might as well pull the plugs while your at it.

 

How does it idle ? What's the warm idle rpms's exactly...yea, don't guess please lol.

 

Yea, if it indeed missing because of a coil and at all rpms, take it for a drive, some where safe and give it hell. Onece you get up to about 45/50 floor it and watch for a blinking CEL. It'll blink 6 times then shut off..DTC is now recorded into the KAM. Scan it, find the cylinder that's missing and immediately disconnect the injector for that cylinder.

That way, you can drive it without melting your converters shut.

If you need coils, get at least OEM spec. That would be Motorcraft or Vista-pro (Visteons).

 

I'll give it a try and get back...... I think the cylinder arrangement is 1234 down the passenger side and 5678 down the driver side from the front looking back toward the engine right?

 

Yup.

 

I haven't goten out to mess with it because of the weather today and for the next few, but will.

One thing I've been curious about for some time. Why are these COP's so susceptible to failure compared to the old round coils or the 60's, 70's, & 80,s. Those older coils lasted forever. I don't think I ever had to replace one because of failure. Planned obsolescence is my guess.