trying to pinpoint repair issues on the '89 K5

[Low87]

A few things I'm trying to iron out, hopefully simple stuff.

1989 GMC Jimmy 4x4
350 TBI w/AC
113k or 213k miles

1) very small amount of white smoke at 1st startup of the day.  I've read a few different causes for this, just want the consensus here.

2) the serpentine belt was squeeling, so I put some belt conditioner on until I can replace the belt.  Now I can hear what sounds like the water pump pulley squeeking.  Does that mean it's bad, or is there another fix?

3) rough idle in gear, smooth under load or park/neutral.  Does this mean tune up?  The PO said he'd just done one, and the wires look new enough.  

Thanks!

[slammed79]

I'm not sure about the smoke, so I'll leave that for someone else.

If you're sure its the waterpump making the noise, I'd just replace it, they aren't too spendy for these trucks, so you may as well do it. Also check the block around the pump for any signs of water seepage.

And I'd just check the plugs to verify condition. Is the truck throwing any codes? That may indicate the source of the bad idle.

[frotosride]

With that many miles the smoke is most likely valve stem seals leaking in to cylinder when set over night or even just when parked for a period of time if they r leaking real bad. This would be the simple side of repairs...the only other thing would br piston rings...

As for the water pump noise...i second a replacement especially if it is the original. the shaft seals in the pump may be on the verge of letting go and thus causing the irritation...

Idle in gear...2 things to check...o2 sensor...they are cheap and easy to replace. don't waste youe money on a 02 socket because it won't fit. if in the time you have had the truck you have never replaced it then it is a good idea because as the sensor gets old it's pulse width increases leaving the ecu to guess at how much fuel to apply to maintain proper air:fuel ratio. IAC valve..this is basically a bypass air valve while engine is at idle. it prevents stalling when loads are placed at idle (a/c/defrost putting into gear). This is basically an electronic version of an idle adjustment screw.

[VileZambonie]

Your noise is probably the belt.

Your smoke could be valve seals/guides worn but you'd have a bluish grey smoke not white.

Make sure the EGR solenoid isn't sticking and a tune up is a good idea if it needs it.