I have a GP GT with the 3800 and the car is getting horrible MPG. Something around 16 MPG It has 28,000 miles and the warrenty is gone already. By looking at the Temp guage the car stays 2 lines before the 185 line. The fans NEVER come on, the car has NEVER seen the 210* mark. And I can let it run for 30 minutes in the morning and the car just starts moving the guage. I'm thinking the thermostat is sticking or something. help me out if you can Thanks.

 

that deffinitly sounds like the thermostat isn't working properly. most series II engines run between 195 and 200 F at all times once warm. we've ran into that concern on the 3.4 engine, but only one time that i can remember of on the 3.8. it'd be well worth the money to give it a try replacing the thermostat.