I'm having a problem with my idle

[Mrp0ck3t5]

So I just bought my 89 galant and it drove great for about a month and a half then started having issues where it started to jerk while in gear and eventually died I took it to someone they firmly believed my issue was in my batter starter and alternator and being it was an older car I had planned on doing these soon anyway. So I switched out all three and it began to start just fine then the idle dropped drastically and now when I drive if I hit the clutch the idle hits down to almost 100 in most cases it dies and then won't restart without a jump and this is with new battery and everything installed what could be wrong???

 

[prove_it]

Check your ground cable

 

[thomcasey]

^^^Agreed^^^ Grounds are sorely overlooked on older cars. Make sure they are all in tact, the cables are not stiff and brittle and that they have a clean connection to the Firewall, passenger engine support, battery and transmission to block mount.

Basically, open your hood and look as follows (looking for fairly thick black wires with yellow line):

To your left, there should be a ground wire going from transmission to a flat spot under the fuse box,
To your right, one wire going from the Silver intake behind the head to the firewall
To your left, a couple going from the wiring harness to the firewall (near the windshield wiper motor)
In the center, one going from where the transmission is bolted to the engine, to the battery terminal.