rough/low idle on 2000 Dodge Dakota

2000 dakota 4.7l. When started after sitting it makes noise like there is no oil in top of motor. sounds like valves chattering. last about a second. Motor never idles high when first started up no matter how cold it is. After warming up sometimes idles at 600rpms and is ok, then sometimes drops down to 500rpms. Also when I'm coming to a stop at about 7-8 mph the engine rpms rev about 200. does this everytime i come to a stop no matter how fast or slow i'm going. Have replaced tps, iac, pcv and taken throttle body off and cleaned.

by in Owensboro, KY on March 11, 2011
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2 answers 1 comment
ANSWER by , March 21, 2015
I had the same problem. replace oil pump
ANSWER by , March 11, 2011
Well the engine noise sounds like the lifters are losing some of the oil as sits and have to pump back up before they quiet down. Older engines sometimes do this, normal wear and tear. I would check for vacuum leaks for other problems but sounds like there is more to it. Is there any check engine lights on while driving?
COMMENT by , March 11, 2011
no check engine lights. runs fine while driving has a lot of power. just wont idle right.