My check engine light is showing a code 34 which says I might have a defective Differential Pressure Sensor. My car is carbed. Where is this thing located?!?!!? Anyone have pics of what it looks like? And how do I go about fixing it? Also, what is the purpose of this SENSOR?

 

Look along the firewall. The sensor should have a single vacuum line routed to it. The sensor is used to help determine engine load to adjust the fuel trim. It looks a little like this:

 

I have the same code on my 87 carb...does anyone have another picture of it? I'm sure i know what it looks like, but i dont know if its to the left of the distributor or if its in the far right corner next to the BARO sensor. They both look the same to me. I cant find a vaccuum line on the one to the left of the distributor, but there is a place to put one.

However, the one next to the BARO sensor has a vaccuum line going into it.

 

Baro sensor is on passenger side; MAP sensor on driver's side. They're identical except the MAP has the vaccuum line attached. Vaccuum line attaches to rear of carb and a lost/disconnected line is the most likely cause of your trouble code.