Hello everyone. My 07 Ranger 3.0 threw a P3040 code and I replaced the camshaft sensor and synchronizer and still have the code and rough idle issues. My mechanic says it may be a valve issue. Is there anything else that will cause this code and rough idle? bad PCM or CKP? Thank you!

 

Welcome to the forum

P0340 I think you mean

P0340 Camshaft Position Sensor Circuit Malfunction

This is a "circuit code" so if you have replaced the Cam sensor and timed it then its a wiring issue or Computer(PCM) issue

Rough running may or may not be related to this code
If you have already changed the 6 spark plugs then its time for Compression test

Cold engine
Remove all 6 spark plugs first, look at the tips of each, any tip that doesn't look exactly like the others is a suspect cylinder
Test compression on each, one at a time, write down results
Expected is 165-175psi
But high number is not what you are after, compression test is all about consistent average
If 5 are 150 and one is 130 then that indicates a problem with that one cylinder

Burnt exhaust valve is the most common cause of one or two cylinders being lower than the others, this causes rough running
Once compression test is done and compression issue is ruled out, you can look at spark and fuel or computer issues
If compression test shows a problem then you won't need to waste time and money on non-fixes like spark and fuel or computer