1994 Dodge Ram rough idle when cold

1994 DODGE RAM
212,000 MILES • V8 • 4WD • AUTOMATIC
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GARDEKUS
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ok i changed the trans in my truck, replaced with a used one. now truck runs really rough till it warms up.
its not so bad when i put it in reverse. after it runs 15-20 min. it will be ok unless i leave it sit for more then 4 hrs. there seems to be some knocking- tapping coming from trans till it gets warn. but then everything seems ok and runs great. i've changed O2,
tps, cap, plugs, wires, roter, egr most anything that would have to do with engine, and im thinking its got to be trans. could trans oil presure cause a rough idle untill it warms up?
Oct 4, 2010 at 12:47 PM
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JACOBANDNICKOLAS
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The trans won't cause a rough idle when cold. Has the check engine light come on? Have you checked for vacuum leaks?
Oct 6, 2010 at 12:41 PM
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GARDEKUS
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I've found no vac leaks, it seems to be good everywhere i check. no engine light or codes coming up. just seems to idle fine when cold if i put it in reverse. bad when in p, n, and d untill it warms up. heard someplace that ecm only reads from 3 sensors untill it reaches temp. just dont know what ones they are. this thing has got me stumped.
Oct 7, 2010 at 11:22 PM
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JACOBANDNICKOLAS
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I believe the sensors are the crank, can, and temp sensors. Of those, the temp sensor would be my first guess. Its purpose is to tell the computer the ambient temp and the coolant temp. From that, the computer determines how rich or lean to make the fuel mixture.
Oct 9, 2010 at 12:19 AM