OT: '98 Silverado question

Tab's open.

It's a '98 Silverado Z71, 5.7L, 4x4, K1500, automatic. I have had the truck
since it was new and it still runs great at 99,000. Yesterday all at once
the ABS light came on, the speedo quit working, and it seemed like the
tranny was jumping in and out of gear. Just as suddenly it all went away and
the truck ran fine again. I thought I felt a light activation of the ABS at
very low speed as I was stopping when I got home. I got a P0505 on the OBD
(Idle control system malfunction).

Any help will be appreciated.

Just a hunch based on past experience, but check the battery cables and
the ground connection. Make sure all are clean and tight. Had something
like that happen with a '96 Grand Am. Turned out the battery had a bad
post and would lose ground connection. Once I figured it out, I could
jump start the car off it's own battery just by hooking up the ground
from the top post to the side post.

Nasty

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