1987 4x4 Pickup idling problem...

Yes, you use that screw to adjust the idle to the proper RPM. Before doing that, check your Throttle Position Sensor, especially the IDL-E2 setting:

No, not unless very severe to cause some other failure. Faced with similar problems, I opted to simply replace all the 19 year old vacuum lines on my '85 with a new silicone rubber set. Fixed lots of small problems and gained about

That is the idle-up valve, it only functions when you have A/C (if present) running or try turning the steering wheel at idle (assuming you have power steering). It boost the idle speed if any of those accessories are running and dragging down the engine idle speed.

New only means that the part is not old. Has no bearing on whether its a good part or whether it was installed and adjusted properly. Invest in a Factory Service Manual and some simple test tools and check them out yourself:

-- Roger

You need a factory manual. The timing gets set first (this may be your problem), Then the fuel mix, then the idle screw should be able to be backed down to 750 rpm. S*it, if you're idling below 750, that's probably it.

Thanks for the pointers people! Appreciate it!

I had a stuck open egr valve on my 88 'yota 22re-- It would idle very low, putt, sputter and shake the shifter like it was coming apart, replaced egr and now it runs perfect...

Hmmm, that's interesting since a plug was found in the vacuum line leading into the valve. It was removed to no avail though. I'm guessing someone somewhere was testing something and forgot to remove it or simply tried to bypass the valve altogether.

try operating your valve with a hand vacuum pump with the engine off.... i tried this and couldnt hear the valve moving so i pulled off the valve and thats when i found it stuck....