350 mag guardian thinks engine is running hot but gauge show good.

[2bseen]

I have been having issues with the guardian putting engine in limp mode because it shows engine is running hot but gauge shows normal temp. It runs fine till it get up to temp then does this, if I bring it down to idle and take off again runs up for about 10 secs then back to limp. Any ideas. Thanks

 

[Scott06]

I have been having issues with the guardian putting engine in limp mode because it shows engine is running hot but gauge shows normal temp. It runs fine till it get up to temp then does this, if I bring it down to idle and take off again runs up for about 10 secs then back to limp. Any ideas. Thanks

First would verify that the temp gauge is accurate with a IR gun on the thermostat housing. If it is not actually overheating likely issue is temperature sensor on port side of thermostat housing. If that was giving wrong temp indication to ECU that would likely cause what you are seeing.