Map sensor no longer reads 100 kpa with key on


So my 87 Turbo T has this really strange issue at the moment that has been going on for a few years. I installed a set of Intrepid Fans and the Dual Relay wiring kit in the car a while back and it seems that the issue may be related to the fan system,

What happens basically is the car runs super sporadic with the AFR and O2 numbers when the fan is not running but once the cooling fan kicks on the car seems to straighten right out and the AFR comes right back to the TurboTweak Target AFR but once that cooling fan shuts off the car runs really weird again and the AFR starts to go quite lean and jumps back and forth.

I looked over the Powerlogger data and non of the numbers seem to be out of wack so I'm guessing this is a electrical gremlin anyone experience anything similar?