Pulling the IAT connector would make infinite high electrical resistance so the thermister sensor circuit should mimic a low temp reading

ECU connector condition on pins X and Y ?

Dip in P is being thought about as you already looked at the transmission connector

Might be at the point of getting the TPS to match the currently sourced ECU

IAC valve clean ?

EGR valve closed

EVAP vavle closed

 

IAC clean but can’t test or it’ll go flying. a new part is cheap so will throw it in

EGR plunger moves freely and rests closed, was also swapped with presumably working unit with no change.

EVAP can be plugged if needed.

 

Hmm. When shifting from N to D timing momentarily retards 6 degrees from when the dip occurs timing retards 6 degrees for a split second.

Oh and the missing is back, crank sensor still has original lucas branding so that’s going into the trash very soon...

 

Ok long story short, idle dips were resolved by changing the IACV which was missing the o-ring. Intermittent misfire and bad fuel trims were resolved by changing the ECU with matching TPS to avoid adaptations.