I just did an engine Swap from V6 to V8 the tachometer is now showing a little higher about 400 rpm more. The truck is an 05 Silverado any suggestions?

 

Does the needle go to zero with the key on /engine off?

 

You likely need a slight tuning adjustment to the operating system inside your Powertrain Control Module or Transmission Control Module, however your vehicle is equipped. It is also quite possible that it really is running 400 RPM higher and you can adjust the idle RPM down a little . . . . . ?????

Rick

 

put a scanner on it and see if the RPM matches the Tach.

 

I'll be putting a scanner to it today to see if it is matching

 

Check to see if the the Tach Output is been corrected from output "4" for the V6 to "3 or 6" for the V8 in HP Tuners