Bad battery cables?

[black g50]

Just replaced starter battery alt and belt.Got the low charge warning so it was due.Problem is,car idles higher at stop lights like it is trying to charge battery.There was green scum on the wires near clamps,cleaned most of it off with baking soda,but haven't looked at the rest of the cables length.Cables are original,would I be able to use Walmart off the shelf replacements? Have noticed trip meter is also dimmer than I remember.

[N/A Q45]

Check the engine grounds and add more. The stock ones are s***- if things are grounded 100% you should be able to take a ohm meter to check from the engine to the main chassis with the car off and then with the car on with no real change ( should have 100% continuity)
I have five extra ground wires, used good thick wire and good clean mounting points, that still is not perfect but it's close.

If the grounds are weak it will not make a good enough connection to charge or use the starter, will turn over slow and you might think the starter if bad but it could be fine.

[Skibane]

AFAIK, the engine speed isn't controlled by battery voltage or state of charge - so it almost sounds like something is causing your higher idle speed.

Do you have a DMM?

If so, you should be able to confirm that the battery has a good connection to the alternator - Just measure the DC voltage directly on the battery posts with the engine idling. It should be in the low-14's with no significant loads running, or at least in the mid-13's with your headlight high beams on.

[black g50]

Can you guys point me in the direction of the grounds?

[N/A Q45]

The only ones I can remember seeing and replacing is the one on from the alt to the chassis and there's a tiny one near the header on the throttle body side. It's a really good idea to replace and add more. I wasn't saying this as a solution to your problem but the car should work better if it is grounded properly

[N/A Q45]

The idling higher might be caused by the idle air control valve. It's on the back of the plenum right near the fire wall, it's mounted on the #6cyl & #5cyl's intake runner's.
Mine did the same thing becuse it was stuck open, all I had to do was remove the 4 10mm bolts, the two intake tubes on the bottom of it and obviously unplug it. Then it comes right out. I used the Right Stuff to seal it when I re-installed.

You can simply test it by just unplugging it and plugging it back in, when it is working the engine will rev up for a few seconds when you plug it back in and come back down to idle in a few seconds about 10-20sec for mine.

[black g50]

When you took yours off,did you clean it or replace? If cleaned what did you use?

[N/A Q45]

I used some good degreaser, let it soak and then used a plastic brush to scrub it out as it was full of carbon to the point the part that moves was stuck so make sure to give it a good cleaning, put a few drops of oil on the parts that move and re-instal.