Upon initial startup for the day, my LRD1 GEM 4.0L tachometer needle will work intermittantly. Especially when I come to a stop. The needle will fall to around 500 rpm mark and stay there, even when I rev the engine. After a while the needle then becomes responsive and works for the rest of the day. Any thoughts on this one?

 

Alternator?

 

Alternator really? I will have to test it later. Thanks

 

The signal for the tach come from the alternator. I don't know how to test it though.

 

Your alternator is either bad or the small wire giving the signal to the tach is ripped or the connector is dirty. It's a small white wire in the back of the alternator.

 

Check belt routing, have you been working on it?

 

The voltage regulator inside your alt is bad, once it warms up it works fine, but until then its not putting out enough power.
If you were to check the alternators voltage when this was happening you would see that it is only putting out 11-12 volts, the battery light on the dash comes on somewhere under 12 volts.
The tach runs off of the alternator.

 

I had the same problem, replaced the alt, all is good now.

 

Sounds like I will be looking for a new alternator and checking out the white signal wire. Thanks all.

 

Had same problem and replaced the alt, fixed my problem. Got my alt from BAP imports for $150 with lifetime warranty.