1994 Chevy S-10 intake manifold tuning control valve

Would like to help but have no idea what you are asking. Could you send pics? Elaborate?

Never mind I found it in the manual, under the fuel section. It controls air flow during certain rpm ranges controlled by the pcm. Thanks though.

The idle speed control motor

The idle air control valve controls the idle through air flow into the intake regulated by a pintle, set through the pcm by the calculation of other sensors. The manifold tuning valve, on I believe 94 and 95 models, controls the passage way of air into the valves depending on speed and rpm.

Found it no testing info will do some searching

Not much on this short lived and zero testing info.
All I got from GM is that a TECH 1 special to GM dealers can read VTCS. Found wiring for relay and solenoid may help.
Relay is either on left or right side firewall on a bracket. Has 4 wires term A pink/blk 12v
term C dkgrn/wht grounded by PCM to close relay and apply volt to VTCS
term D pink/blk 12V
Brn/wht 12v when relay is closed. This wire goes to VTCS which is grounded G117 right rear cylinder head.
Ohm checking and voltage checks will verify if relay and solenoid are operable. And no signal from PCM on C would mean? Either PCM has not reseived info or is faulty. Must be operated by MAP and VSS so if MAP is not signaling vac change in manifold in relation to TPS and vehicle speed may not operate.
That's all I could find hope it helps

Yeah man thanks for the info. My map sensor at idle is 3.8v. Its supposed to be 1 to 1.5 v at idle. I think its telling my computer I have low vacuum. My vacuum is a steady 18.5psi.
The only info I got about testing the manifold tuning valve was to check for voltage with the engine running and to remove it and check for proper valve operation.
Thanks for the wiring info, my wiring diagram has only two wires to it. But you are right there are four.