I have a 2005 impala 3.8. The car runs fine, it does not overheat. The warmer the weather the worse this gets. After about 10 minutes of driving the temperature gauge goes down to nothing, the fans kick on and ac quits. When it is cooler, 70s the gauge will come back up, not when the weather is warmer 90s. I have a new temperature sendor an pigtail and thermostat, same issue, wiring appears good, any ideas, ecm maybe? Don't want to just throw parts at it.

 

[QUOTE=b004508;449006]I have a 2005 impala 3.8. The car runs fine, it does not overheat. The warmer the weather the worse this gets. After about 10 minutes of driving the temperature gauge goes down to nothing, the fans kick on and ac quits. When it is cooler, 70s the gauge will come back up, not when the weather is warmer 90s. I have a new temperature sendor an pigtail and thermostat, same issue, wiring appears good, any ideas, ecm maybe? Don't want to just throw parts at it,almost forgot the most important part, it has P0118 code too,

 

is the code active all the time or stored?
when the vehicle has sat overnight...key on and compare all the temp sensor inputs. ambient, intake air, ect... are they all similar?
find the coolant temp sensor...disconnect it...jumper the connector pins...does a circuit low code set and the circuit high go stored?

 

Sorry it's been a while, have been busy. I have the 2005 impala with the temperature issues. After setting over night all the sensors read correctly. I jumped the temperature sensor wire no p0117, it goes to 286 degrees. I forgot that it also throws map sensor code at the same time . Thank you, any ideas?