I did a head job on the 350 in my Suburban,88 with TBI. Since all things have been put back together, whenever I am in reverse it idles real rough and sometimes stalls. Also if I hit the gas and then let off quickly it stalls. Any help would be appreciated. I have replaced the MAP sensor and TPS and also the Idle air control. Please send your thoughts before I end up in the garage for some costly diagnostics.

I think the problem is with a vacuum leak somewhere. Did you use the rubber gaskets on the ends of the intake manifold, or did you use a bead of silcone RTV on the ends of the intake manifold? I use a bead of silcone RTV on the ends and throw away the rubber gasket ends of the intake manifold and use regular intake manifold gaskets on the sides of the intake manifold, with just a light smear of silcone RTV around all intake ports and water ports. This really helps keep vacuum leaks from happening. There are very few vacuum hoses on the TBI, so is it possible one of the vacuum hoses is leaking?

To help find problems after some engine repair has been, I often check everything that was done during the engine repair. I once got a water pump gasket out of place when I rebuilt an engine that caused the engine to run hot. The water pump gasket was blocking the water flow. Things happen when doing engine repair. Could be the TBI problem is not related to the sensors but to a sensor wire? How did you set the rocker arms? It could be that one or two of the valves are not closing, and the engine is not making good vacuum.
dave