How do you unhook this wire on I.P.
 

I am taking my engine out of my 85 300 SD and this last wire to be unhooked has me a little stumped as to what it's purpose is and how to unhook it. It looked like it was just a plug with 2 wires inside it going to the I.P. I thought if I just tak 2 screws out it would unhook pull out k took the 2 small screws out and it does not seem to want to come loose. Ounce I get this unhooked I can pull engine. I do not want to cut the wires if I do not have to.
Just went out to study closer and I was able to get the wire pulled out it has 3 prongs or tabs on it that are curved I guess thats the way its supposed to be as I never had any need to take this out before and I have no idea what it does maybe someone else can shed some light on this.

They are for the fuel rack position sensor, part of the EGR system. The connector is on the RH rear corner of the engine compartment. (mounted to the first firewall)

http://www.startekinfo.com/StarTek/outside/12253/program/ETM/126td83-85.pdf

Pages 108 and 207 of the electrical manual (C158)

I unhooked it at the pump easier then at firewall just seems like more pollution crap that you don't really need.

I'm not sure that side is a connector. The screws might have just been for strain relief. You might have tugged the wires out of a circuit board. Anyway, that rack position sensor is just for EGR control, so if you eliminated that (like many), it isn't needed. I put an older engine w/o that in my 1985 and runs fine, but my EGR is "temporarily off".

BTW, that temp sensor in fwd part of the block (left of photo) is also for emissions, and the earlier engine didn't have it. The aft one is for your dash gage.

I won't worry too much about it then thanks all.

Exactly what happened. There is only one connection that can be removed and it is located on the firewall.