Rpm needle going crazy while driving. Rpms not going crazy just the needle.

LR also dies sometimes while starting it. Actual rpms putter down and LR dies. It is worse with the AC on.

It helps if I keep my foot on the gas sometimes.

 

Your tach gets it's signal from the alternator. Check the connection (smaller one) to make sure it's making a good connection.

 

​​​​​​​That's good advice right there and damn near certain the cause...

 

It's either the alternator or the wire connector to the dash card.......

 

My 98 D1 would do that. I changed the idle air control valve and it solved my issue

 

IACV could be the source of the "weak start", but generally it is more persistent than exclusive to start up. For example, mine would stall at the end of an off ramp

Erractic RPMs is likely the connection to the alternator as suggested.