Ecm computer location in van and where to buy

Also there is a silver box under the seat that looks just like the Ecm but mechanic said without looking he didn't think was it. I think it is it looks just like pics I've seen of Ecm computers. Is that somewhere it could be located? Or is there more than one computer in this vehicle?

The 1992 G30 5.7 Van uses the the standard OEM (Factory computer) this is not a "special" PCM (powertrain control module) its easy to locate a replacement or can likely be repaired. Locate a facility that knows engine management controls and the old basic TBI injection. The PCM /ECU is located in the right hand side of the instrument panel enter through glove box (passengers side) not sure what you're viewing under the seat.

my '93 GMC runs fine after almost 25 years and 170,000 miles- and it still gets 25mpg on the hiway- the throttle body injection is almost bulletproof on these- I don't know your mechanic, but from the list of work you mention it sounds like somebody is just guessin'- please stop guessing, find a better mechanic- but they may not be able to undo whatever has already been done to it- this would not be a problem if it was a regular van, you could just get rid of it because it is not worth much- but because it is an RV, and you want to keep it, you are kinda stuck- if it can not be repaired in a cost-effective manner, you may want to think about customizing it- put in a high performance crate engine with a carburetor- and you would have a new engine- good luck

@Jamnblues I travel so I don't have a regular mechanic the sensors were me trying to figure it out. The mechanic just rebuilt the throttle body replaced a full injector, put new plugs in, and replaced my iac because he trust the one I put in. @auto_centric thank you I will look for it on the passenger side of the car. There is no glove box on that side sof Idk I'll find it. My main question was if I could use the computer for the regular van. I found a site that sells reman ones. Thank you.