I've had a problem for some time that is annoying! About once every week or 2, my check engine light comes on and the code it throws is "Map Sensor voltage to high". After a couple of key cycles, the check engine light goes off and all is normal till it happens all over again. I've replaced the sensor and it has still been happening. This has been going on for about 4 months. The truck runs perfect.....no evidence that anything is wrong except the check engine light. The bigger issue is that when the check engine light comes on, the fuse on my TST box blows out whether or not the box is turned on. I've sent the box back to get checked out and all is good there. I've now pulled the box out to be sure that it was not the problem and I'm still having the same problem. I also have a shop manuel but there is not a wiring diagram that shows the map sensor and what could be tied into it. Any good techs out there. Stumped!!

 

I would be checking your map sensor wiring, from right at the sensor, through the loom and down to the ECM. Also check plugs for corrosion.