87 chevy 1/2 ton rough idle/low idle

[teamontherun]

First off the forum has a ton of info. im glad i found it and im glad all you members keep in so informative.

I just bought an 87 chevy 1/2 ton v6 tbi. it runs well and is a pretty sweet truck. The only issue is with the idle. it feels rough like it is too low. i dont have a tach so i dont know what its idling at. Also it feels like it runs rougher after a drive. Today i drove about 30 min and when i got off the freeway it was feeling like it might stall. it didnt but it was right on the border.

Another thing that might help is that when im stopped and turn the wheel it gets rougher and sometimes when im parking i turn the wheel all the way to the stop and it will stall. Its because the power steering pump is working harder i know, but i also know its not normal.

Any help will be greatly appreciated.

(i have access to digital voltage meter, vacuum gauge, timing light. just so you know)

[Captkaos]

Pull the Idle Air Control valve out of the TBI and see if it is dirty.  If so spray some carb cleaner on it and see if that changes the stalling.

BTW, If you are interested, and good with wiring/soldering, you can make yourself a OBD scanner with a few wires and electrical probes and WinALDL free software and a computer.

[DnStClr]

Also make a check for vaccum leaks at the vacuum hoses, connections, and base of the throttle body by spraying the carb cleaner at the connection and see if it gets sucked into the joint. We've seen that vacuum leaks are a common cause of rough idle problems.

[VileZambonie]

check your ignition components first, cap, rotor, plugs, wires, etc...

[teamontherun]

well im pretty sure it was a vacuum leak. i found an open vacuum "port" right next to the one that goes to the egr valve. i plugged it and it ran great. if someone knows where the plugged one goes to let me know.

[DnStClr]

It might be the line that goes to the pcv valve. There should also be a hose going to the emissions cannister, and one going to the map sensor. I hope the pic is big enough...
http://memimage.cardomain.net/member_images/9/web/2205000-2205999/2205426_9_full.jpg
I think there are other vac. lines too- like vac advance and one going to the tranny. So that makes about 6. There might be one more and I forget what it is.
  1. egr
  2. pcv
  3. emissions cannister
  4. map sensor
  5. distributor vac.advance
  6. tranny