Ford Repair: camshaft position sensor, rubber mallet, fuel mileage

Question
QUESTION: I have a 2004 Ford F250 with 6.0 liter diesel.  Lately I have noticed a little up and down in RPMs when sitting at a stop light.  It's not much but enough to notice.  I have a Superships that's show a cam position sensor error.  I've cleared and a day later get the error again.  I thought once the sensor went out it was out.  Also, will this affect mileage?  I have noticed a drop in about 4 mpg in the last few months but don't know if it is related.
Thanks

ANSWER: it can leave you on the side of the road if it is actually going bad-ford has had some trouble with cam sensors and i don't know whether that one has been giving trouble or not-yes it can affect your fuel mileage and no the sensor isn't good or bad-it can intermittently give problems for a long time.

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QUESTION: So we I put in the new one...do I need to seal it up with silicone or just tighten the bolt good?

ANSWER: just bolt it up be careful and don't break the one coming out.

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QUESTION: I appreciate you helping me out.  I don't have a lot of money so anythng I can get a clue on without paying big prices of a dealer is wonderful.  I have another question.  I am getting a lot of road noise, some creeks, and squeaks, etc.  Some thumps when turning sharp onto a bumpy road.  I really feel the highway.  I just had all the ball joints replaced and new shocks put on the front.  Does this usually mean I need to get everything lubed?  Will that even help.  The truck has been used really hard (before I got it).  Again, I would appreciate your opinion.

Answer
your welcome

as far as the noises there is so much under there to make noises i don't know if i can help it needs to be checked out-i would definitely check end links on sway bar-you can also take a rubber mallet and get under the truck and tap different parts until you hear the noise that helps alot sometimes pinpointing it. i received two followups from you and i will read the other one again to make sure i didn't miss anything if it is the same i am going get rid of it but you may get a notice of non answer or something just ignore it.