That will be a waste of 9 COPS.

 

Yes, I agree.
Code scan it for set codes and pending codes.
If it is actually misfiring you will see a code for "random misfire detected" and usually a cylinder # misfire code, neither of which will light the check engine light on an OBD1 system.

 

To educate me is OP's truck more than likely to be OBD-I and not II ??

 

Yes, it is most likely OBD1 unless it is California spec. Since OP does not have his profile filled out and did not specify OBD 1 or 2 most will speculate that it is OBD1. Vehicles over 8500 lbs GVWR are not required to be OBD2 compliant for most of the USA.

Also, the thread was somewhat hijacked my dmags which is what my last post referred to. "Parts swap diagnosis" where someone just throws parts at it without actually diagnosing the situation correctly is a waste of money and can be detrimental. dmags issue is most likely 1 (one) bad COP in my opinion. The way I would diagnose that issue is trade the COP from the misfiring cylinder with any other cylinder, drive it and code scan it again. If the fault follows the COP, replace that (one) COP. If not, you have a different issue and you didn't waste any cash on a COP you don't need.

Although it is a good idea to have spare parts whenever possible, it is not absolutely necessary in this case to identify the problem with reasonable certainty.

When I first got my 1999 F250 running (fixed blow'ed out plug) it was still misfiring. I kept waiting to see the check engine light come on, but a persistent single cylinder misfire that happens with a failing COP will not light the check engine light on an OBD1 system like it will with an OBD2 system that people seem to have come to rely on. I know I have.

That fault will set a code or it will show a pending code in an OBD1 system. without lighting the check engine light. I found this out by persistently checking for codes because I could tell it was misfiring and I wanted to determine if it was the on the cylinder with the blow'ed out plug I had just fixed or some other problem. And it turns out that I correctly diagnosed a failing COP.
Wondering why in the fudge it never lit the check engine light, I read a lot on this forum and discovered about the OBD1 system on most of our trucks. It really does pay to research an issue before posting questions about it. So once I read about the difference between our OBD1 compliant trucks and the OBD2 system I thought I was dealing with, I then knew to read the codes more often to check for issues instead of waiting for the idiot light to tell me something is wrong.

Code scanners are cheap enough that anyone can afford to keep one in each vehicle they own. Either use the $15 Bluetooth adapter and the FREE version of Torque app for your smartphone or get a cheap $20 standalone code scanner. My standalone does not explain the codes meaning but it will read set codes and pending codes AND clear any of these codes which is usually all I need it to do. The Torque app will explain what the codes mean and also do much much more.

If someone can afford to buy 9 extra COPs that are almost certainly not required, the small price of a code scanner is pretty much a no-brainer and should be the first thing you reach for when diagnosing a modern computer controlled vehicle.

 

Probably, unless it was originally manufactured for an intended first sale in California or one of the "Green States" that required California emissions.

The OP needs to look at the VECI label on the underside of the hood to find out for certain.

Ain't that the truth!!!

 

I would highly recommend getting the torque app for an andriod device and the bluetooth OBD device to plug into your rig. Fairly easy to diagnose the misfire count using this tool.