My car is running fine sometimes and out of nowhere it will run like crap and hesitate, and I have no idea why. Let me start off by saying its a LE3 383. The only code I'm pulling is Map Sensor voltage too high, and this only sometimes. The map sensor is at about 3.3 volts at idle when I check it. When the car runs bad, the check engine light comes on and trips that map sensor code. The car doesn't want to idle when it does this and I can floor it and it doesn't want to rev past 3000rpms. I did put a vacum canister on the car and this didn't help. My question is that if the cam isn't making enough vacum, wouldn't it always be not making enough vacum? Why does it come and go? The car hasn't done this in 4 days and now it did it again. This makes no sense to me. Anyone have any ideas?

 

Anyone?

 

Map Sensor too high might be caused by poor wire connection (intermittent open). Fred has a good write-up on the MAP function here:

http://members.aol.com/InjuneerZZ/Sc....htm#step%2010