Any ideas?

[gpgtp_22]

I just replaced the hg on my 1990 turbo. First start up car wont stay running unless i help it to, very sporadic idle dies right away after startup. I took it out for a test drive to see if that may fix it but it was very hard to even keep running while driving. I got back and the temp gauge read normal but when i opened up the hood the radiator was steaming and steam was coming out of the overflow. The turbo also seemed hotter than normal as well. I checked all my connections and noticed one connector was unplugged but i cannot find where to plug it to. It is a grey oval connector under the rear of the intake manifold. Let me know if you have any ideas to any of the problems. Thanks.