TPS fluctuate on ECU but not in the multimeter

Here is my problem when I'm in fully closed and WOT fluctuate around 0.02 volts when connected on the ECU when I tested the TPS on the bench everything looked ok! My question is could this be due to grounding issues? the wiring harness is the original from 1993! If for some reason looks like a grounding issue what would be the best way to track and solve the problem?

What engine, what ECU? Can you read throttle percent in the ecu?

Engine is B20 vtec running Jenvey ITBs, ECU is the factory one running a daughterboard! TPS percentages fluctuates 0-0,5% with throttle closed and 100-101 percent at WOT! TPS voltage for closed Throttle is 0,39 volts and WOT 3,89volts. The Ecu gives a MIL code only if the tps goes over 5 volts!

I attached a link to the tps Datasheat

Have you seen any problems from this? It doesn't sound that bad...

Yes mainly I notice this when the car is idling I have a fixed idle using the throttle bodies to help the car idle an due to this the car sometimes has idle some other times the idle just vanishes. Also on cruise I see the car sometimes slowing for a bit or accelerating a tad more!

You need to post screenshots of logs showing this. I'm not sure how the idle can vanish. What does that mean? Does the idle air valve duty cycle suddenly change? Does spark timing change? Same question applies for the cruise control.

I'm not convinced that the ECU isn't in a dead band where it ignores the fluctuation.

I've uploaded a log I hope you can give some insite thank you very much in advance