Mazda Repair: mazda 6 2003 idleing problem, oil starvation, cam sensor

Question
The engine is a 4 cylinder, and the only noise is the idleing sound of the engine reving up and down, and the check light is off... i need help quick..lol... i go in to get the used engine quote tomorrow!  i went today , and asked if there was anything else i could do , and he said no,. too much sludge build up.  thks for taking time to answer.   quincy
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Followup To

Question -
I took my car to the dealership after a check engine light came on.  they told me it needed a new cam sensor. got that replaced, and the car is still idleing extremely rough anytime i stop. driving full throttle it runs perfect.  took it back to the dealer , and now he tells me i need a new engine, ..that the problem is oil starvation?..could this be true.... thanks for ur time.

quincy h.
charlotte nc

Answer -
Hi quincy thanks for asking
I think this mechanic has no idea what he is talking about.. I need a little more information,, DOes the engine make any noise on idle or highr RPM's? is this a 4cylinder or a 6 cylinder? Did the check engine light sray on after you got the vehicle back?


Answer
Hi Quincy thanks for asking.
If there is anything of a ping or a slight knock in the engine and any RPM then the engine will have to be changed, The noise is caused from a blown bearing that has actualy starved of oil. from a blockage in the oil gallery. I have already had to change a few of these engines for the same problem. A sludge build up problem is usualy due to a lack of maintanece or not doing the oil changes on time.  This is a 2003 it should be under warranty!
good luck
Chris P