1998 Pontiac Grand Prix engine swap

was the grand prix the same size motor? 3.1j engine 3.1m engine or 3.1e engine. the eighth letter of the vin is the engine code. these problems you are having we should be able to fix them all but i need to know exact size engine to get p[roper wire diagrams. the tach is run through the ignition module and i would assume all 3.1 engines used the same ignition module so that is the first thing thats odd. the temp gauge is most likely a bad sender switch and can you swap the old egr valve into this engine? is it a electrical connector problem with egr or do the egr ports not match up?

theengine i put in the grand prix was a 3.1j and the egr ports are different and so is the plug.

didnt the new engine come with a egr valve? if not then you will either have to swap intakes with the other engine or but a new valve and wiring connector, or get used ones from junk yard