My 1998 Disco was running super rough and wouldn't get over 35 mph. It turns out that one of my spark plug wires became loose. I reconnected and it began to run better, but still sluggish. No engine light, but I checked to see if there was a code anyway. It produced a P0340 - which is a Camshaft sensor error. I cleared to code and now it is running fine.

3 Questions- could the disconnected spark plug fault throw this code? Why did it continue to run poorly after corrected? Does the P0340 fault code put it into some form of a "safe mode" ?


Thoughts?

Peter

 

Yes that could have throw the code.
NO it should not have continued to run rough after fixing.
However if that spark plug was extremely fouled it could have ran rough until the spark plug was clean again.
I would not worry about it unless it happens again with no obvious reason.

 

Cool. I wish the camshaft sensor wasn't so expensive I'd just replace it. I found a used one for 100.00 new is $300. So, just the thrown code puts the truck in a weird safe-mode?

 

The cam shaft sensor is failing, a loose plug wire will not cause a 340 code.
So start saving your pennies cause you have a purchase coming up soon.

 

Would you go with a salvaged sensor ~$100+, or new ~$250+. used has 6 month warrantee

 

Is there a wear factor involved with that sensor?

 

I'm not sure how the cam sensors wear out or if mine just failed. I'd defer to mike or spike. Perhaps putting in a used one is just moving the failure event down the road. My truck only has 90k miles. Who knows how many miles on used salvage donor truck.

 

A used one with a warranty is a good way to go. As for the other question, there is no wear factor on this sensor, it works on a magnetic impulse signal.
Wait till the engine starts acting up again and throws another 340 before buying one cause even used, they are expensive, want to make sure this was not some sort of glitch first.

 

check the connector at the ecu for damage. seen a few of them rot away causing the same issue. a little water will get in and cause the same problem.