Tuning for performance & (reasonable) MPG?


Well-known member
After an overnight cold soak, use a scan tool and access vehicle data stream and see what they read before starting your engine. They should be within a few degrees of the other. and that should be close to your ambient temperature. The ECM doesn't set a code for them unless they fail open or read higher than operating parameters.

I did it this morning. Do these numbers look correct? Any feedback would be appreciated.

Before starting this morning:
Ambient temp: 66F
Coolant: 62.6
Intake: 55.4

Fwiw, I noticed while driving steadily at 65mph, the IAT would fluctuate slowly between 62-77. Despite ambient temp staying the same.

The coolant was fairly steady between 188-192. Thermostat is a new 192 motorcraft.


Famous Member
Are your connections at the sensors good? I would like to see the intake reading closer to the ambient before start up. Your ECT looks like it's working as it should.