I went to nashville the other day and on the way home, my truck would jump, jerk and try to stall. I would throw it in neutral and gun it for a second and it would smooth out, the drive for a hour and do the same thing. Now it does it every couple minutes.

I ran the codes and got
KOEO: 21, 24, 31
CMC: 14, 18, 22


I have replaced so many parts in the last couple years, just ask i will let you know if it was replaced.

I really need help!

 

Seems to be a theme here lately; but start with diagnosis and the basics: Compression, Spark, Fuel..

Lots of things that can cause those symptoms.

Rather than jumping in and replacing parts; do some checking

Any changes made recently?
Compression good?
Ignition good (good spark?)
Timing set correctly?
Fuel delivery ok?

More details as to the vehicle / engine would help us to know.

In general, the codes you are getting are: (may be different for YOUR vehicle - hence more info needed)

21 Engine Coolant Temperature out of range
24 Intake Air Temp out of range
31 EVP sensor out of range

14 Ignition pickup was erratic
18 Check base timing and advance
22 MAP vacuum or BARO signal out of range

 

Sorry, it is a 1985 ford f150 xlt larIat with the 302 5.0 fuel injected. I will also try to get those tests done

 

With all those sensor codes, I would check the wiring harness around the engine, and the little ground wire over by the battery area. Those sensors use a common 5v power wire from the computer, so if there was a bad connection, the computer would think all those sensors have failed. All of them failing at once like that would be a very rare occurrence.

 

How do we know they all failed at once? Computer stores codes.
I agree it could be a computer or wiring issue, but I've also seen vehicles have several issues like this.

You could try and clear the codes and see if they come back.

I'm not a big computer fan however. I know the codes are supposed to help with diagnosis but they've been known to lead you astray as well.

It it were me; I'd diagnose based on symptoms and go from there. The computer controls ignition and carburetor settings as well as emissions. That's about it.

If compression checks out, I'd look at ignition next. Cap, rotor, wires, plugs. I'd also check the timing. If the timing is off, and it's computer controlled, you need to start looking at wiring, connections, sensors, etc.

Since it's fuel injected, I'd check injectors also. Then of course there's the throttle body...

Again; basics. Since this IS computer controlled, I'd add Connections / Wiring to the basic checks.

So:

Computer / Wiring / Sensors
Compression
Spark / Ignition Timing
Fuel - injectors / throttle body / filters

But that's just me..

 

The computer is the first thing to check on these engines. The fuel injected trucks won't run without it like the old carbed/computer trucks would.

The codes are a overall picture of what the computer sees. It will not tell you the exact problem, but you can surmise what the problem might be. I would work on the codes first and try to get rid of them.

I would check the spout connector and make sure it's there for the code 18. Code 14 can also be a wiring problem from the dist to the computer. I would really check that wiring out.

 

Yes, 14 & 18 are serious errors to be getting and very well could be indicating your running problem, my gut feeling says to have the ignition module checked out at a parts store. You will need to remove the module to do that (which is probably gonna require a special 5.5 mm socket wrench, $5 at the parts store) but that's my gut feeling based on having dealt with those types of errors before, and is assuming all the wiring and everything else is correct...

But Dave also brings up a good point - look at all those other error messages, it's complaining about a lot of other things, too.

But wait, there's more.... what you have abbreviated as CMC - is that supposed to mean some sort of Continuous Self-Test?

Reason I ask is....

The Ford shop manual says there is no such thing as an error 14 or 18 possible in either KOEO nor CM for either a passenger car or light truck, the ONLY place it is possible is in some sort of continuous self-test (which I've never done).

Which makes me raise one eyebrow in a Spock-like fashion and wonder if you have the correct computer in there...

And reading the comment saying a lot of parts were replaced the last several years makes me wonder about some things, too... were those attempts at fixing other problems? Or, did replacing all that stuff cause these problems? Lots of possibilities, too little information..... and the results of the KOER test would also be good.....

 

I am going to guess and say CMC would be Continuous Memory Codes? My book also says code 14 can only be stored in the memory section. Code 14 is the steady pulse that goes from the dist module to the computer(they call it the PIP). The computer takes the PIP pulse, modifies it, and sends it back to the dist module as a pulse also, to tell the ignition module when to fire the coil(controls the timing of the engine). This modified signal is sometimes called the SPOUT and this wire has a jumper plug in it near the dist. You have to unplug this jumper when you time the engine, to take computer control away from the computer, so the distributor can be set according to the sticker on the radiator, and then the SPOUT jumper is plugged back in, and that gives timing control back to the computer. If this jumper is forgotten about and left out, you will get a code 18.