Hey guys have a few questions . Have a buddy of mine that bought a used 95 accord v6 auto that had a bad engine . He was able to pick up a junkyard motor with low miles from a 97 accord also v6 that we had swapped in to the car . Here is my problem everything is connected as it should be when we start the car it has a rough idle and revs up to about 2500-3000rpm then cuts out . I was able to pull engine codes from jumping the connector on the passenger side all that it brought up was :
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*Intake Air Temperature (IAT) sensor
*Engine Coolant Temperature (ECT) sensor
*Code 12 (Exhaust recirculation system
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Not sure if those would throw it in limp mode but any help would be appreciated . The dizzy is new wires and plugs are good it hold oil pressure as we ran a test on that aswell but not sure what else we should be looking for there isnt any vacuum leaks checked that aswell so we kinda hit a brick wall here just looking to see if anyone has had the same problem

 

Being a Speed Density system it heavily relies on the MAP, IAT, to guesstimate what the actual mass of air is. Density of air changes with temperature change this will greatly affect how the engine runs. Combined with the lack of an Engine Coolant Temp sensor the PCM does not know how much air or how dense it is. Usually when the ECT is bad it will cause a no start condition.

Find out why the IAT and ECT are not working. If these sensors are from the junkyard engine, reuse your old bad engines sensors. If you are using the junkyard engines wire harness, verify it is not damaged or has shorts. If it appears to have damage, replace it with the original bad engines harness.

Unless the EGR valve is stuck open at idle, it should not affect the engines running at idle.