Newbie here...Hope I can get some help. I have a 1980's (I think 1986) TPI manifold on my 305. First question is what year? How to identify what year it's from. Second is, I have two plugs that seem to go to two sensors in the front of the manifold. Both sensors are oval in shape but my plugs are not. I have one oval and one square??? It runs great when first started then when warm the idle roams a bit. Otherwise runs great. I need help please.

 

One sensor is for temp gauge/light, depending upon original car,
Second sensor is cold start for ECM, aka, a cold sensor telling ECM for enriched fuel in cold running, as pulling choke plate closed on a carb.

 

Thanks "Everett". I was hoping for that scenario. It starts and idles about 1200rpms then drops after 30 seconds. So it must be right so far. I have another temp sensor to my gauge so the one is not needed. Are both of these sensors the same? They are both the same style. It would seem that they are so close together that they are both read the same.... assuming they are the same sensor if course. This helps greatly. Any idea how to identify what year I have? Is sitting on a 1978 305ci. thanks again have a great day...

 

You should check any aftermarket auto parts stores and check similarity of the two sensors.
Obviously, the one for the ECM will be with the year/model of engine and other sensor would be for the model of car for gauge/light.
idle action seeing is good as by design, engine should be off fast idle in 90 seconds.
A Haynes manual would explain this action also plus other circuits and 'How-to's' for the rest of vehicle.
you're welcome.