89 S10 4.3 Need help troubleshooting TBI/IAC Idle issue

[ChevyTech]

Re: The dash gauge reading wrong.
The display like in your truck where a problem before those truck even got old.
They look nice.
They are a high failure item.

If the sender resistance reads even close to where it should, then suspect the instrument panel as the problem part.

So, you think the fuel pump works at higher volume/flow, but not at low volume/flow? It sure works fine at anything above 750 RPM when in gear, AND at 750 RPM when out of gear.

No,
At idle the injector pulse is so short that when the pressure is low, TBI systems go very lean. At high rpms & loads the injector has much longer pulses, spending more time open, and they do better with low pressure then at idle. That's the way it is. Do a search on my threads and see if you think I know what I am talking about. I am giving you my honest opinion. I have no reason to steer you wrong. I know nobody that knows the TBI trucks better then I do.

This is not a carbureted engine you are working on. You are thinking about fuel supply like it is carbureted.