90' Suburban dies, check engine light comes on.

[SoCalSlaughter]

Ive been fighting this with my truck since 2008. The truck just recently passed CA smog. Its a 1990 Chevy Suburban V2500 5.7 - TH400. While driving, the engine will have a whistle sound like it has a turbo, when I let my foot off the gas, the whistle will get louder. If I sit at a stop light for to long, the truck will either surge and kick the rpms up, or it will bog and throw code 42 (Spark controller). Shut the truck off, and back on and the light is off. Also, randomly while im dirving the check engine light will come on and go off. I checked the code and its code 13 (O2 sensor). Ive replaced it many times, followed the single wire all the way back to the ecm. I cannot figure out whats going on here. The truck at times, at a light will surge and then die. But always start back up. Ive replaced dizy cab, rotor, distributor, 3 IAC motors, 4 ICM, EGR, ECM, 4 O2 sensors, water temp sensor, fuel pump, fuel filter, spark plugs, wires. Ive added more grounds to the body and engine from the battery and still doesnt help. Sometimes the truck will drive fine for an hour, sometimes I worry if it will make it home. Help me!!! haha

[panhandler62]

This is only a general comment since I don't know the details of that model but -- the symptoms sound similar to a vacuum leak with a carbed engine.

Another off the cuff thought is a problem with the fans.

Can you replicate the symptoms while sitting still?

[SoCalSlaughter]

The truck has the TBI unit. And problem with the fans? And sitting still? If I start the truck and dont put it in drive, it will idle fine with no problems, once I do some driving, the truck will start to have this problem. It will die sometimes also sitting at lights.