So the story begins like this. Customer says the engine has a miss fire. Hooked up scan tool and found P0340 for the cam shaft position sensor. Got a new sensor from napa and installed it. no change. Read to post on this problem and found the synchro assembly could also be bad. Got new assembly with new sensor and install tool. Installed new part and still no change. Had vehicle sent to Ford dealer locally and they said cam sensor synchro assembly needs replacing. had them install new one still no change. They said it also needs a computer. Got vehicle back and luckly had another vehicle of the same year make and model with the same engine. swapped out computers and still no change. took off timing cover to inspect the timing chain and timing marks and all is ok. I am at a loss for words. Any ideas out there I would greatly appreciate it.

 

I would think at this point just maybe you might be getting a false P0340 code.
Some of the cause for this could originate from the alternator or the coils.
Since there is a misfire problem you might start with the coils.
Alternators that don't function correctly can give off signals that are perceived as a P0340 code. Worth checking into.

 

I did also replace the coil assembly but there was no change. I guess I will assemble the timing cover back together and check the alternator. At this point I will try anything.

 

What are you still chasing ? The misfire or the code or both?
What kind of test equip do you have to work with?

 

I am trying to figure out the code. It really seems like there is a miss fire but no codes. I have a snap on ethos scan tool.

 

I don't believe a scan tool will help isolate this problem.
A bad diode in the alternator has been known to generate a false P0340 code.
Sound crazy , but that's the crazy thing about electronics.
If the tool will tell you whether you have too much AC coming from the alternator that would help. Also, try making sure to separate any wiring coming from the alt from any ign wiring.

 

Well I got it figured out. It was a bad alternator. Problem fixed. Thanks to everyone and there help.

 

So I soke to soon. I put the new alternator in the van and a week later the customer is telling me the check engine light is back on the van runs the same now. It seems like this van is from hell. Please help. I am not about to send this vehicle back to the dealer but I am also tired of putting parts in the van that are not fixing it.

 

Now another sympton is that with extended idling the van will stall out and die. Could plugged up EGR ports cause the faulty p0340 and make the van run lick crap but also not throw an EGR code?

 

Could you check the fuel trim for excess correction of a lean condition?
What are the readings you get? Both banks. Long and short .
A quick and thorough check of the PCV hoses from end to end is something worth checking also.
Look for a cracked or broken hose there. Doghouse removal may be necessary to do this
There are many reasons for a P0340 code to show up.
You might also check the plug connections at the PCM and also check the DPFE , if shorted will cause a P0340 code because it causes a number of sensors to go down with improper voltage to them also.
It makes one wonder if the alternator you installed isn't questionable since there was no problem for a whole week.