Gas Mileage Is Down 5 MPG

[Linewalker]

When my gear selector is in o/d, my scan tool(s) shows it's in p/n.

My question is, can this have any effect on my being able to properly tune the car? Will the computer try to compensate somehow because it thinks the car is in p/n?

When I drag race the car,it seems to run strong and pull hard. I drag race in 3rd gear not in o/d. My gas mileage seems to be suffering for some reason.
18.5 mpg on the highway at 65 mph in o/d. It used to get around 23 mpg.

I changed to a Impalla SS maf/translator and installed a new Denso 02 sensor. My mpg still sucks.

Thanks

 

[Chuck Leeper]

Lockup converter?

 

[Linewalker]

Yes. I have the stock D5 convertor.

 

[Chuck Leeper]

Is it..

Yes. I have the stock D5 convertor.

going into lockup?
AIRC, if the ecm does not get the gear signal from the switches in the vb, there is no lockup...

 

[Linewalker]

Yes. About 2000 rpm at 60 mph. I replaced the tcc solenoid about 6 months ago.

Thanks for the ideas though. They are appreciated.