1992 cheyenne 1500 wt chevey truck

May be a worn out engine and is blowing burnt oil out the exhaust. May want to check the engine compression.

The engine would need to be checked over to determine what the cause is. It could be low fuel pressure, bad injectors, the fuel regulator may need to be rebuilt in the TBI, or a vacuum leak, or even a weak spark. Are you going to be doing the checking on this? Like need to know where to start, and can you do this kind of thing?

It could be low cylinder compression, start by having the engine compression checked to see if it is even worth trying to fix. Especially if this is the original engine.

Im not i just got this truck and hope its a good one i paid 500 hope its a spark plug my luck its not im broke and bought it from a good friend

Start with checking the engine compression. You can look at the condition of the spark plugs when you pull them out to check compression. The spark plugs would have to be pretty worn to be the cause. They are probably black but there is a cause for that. Everything mentioned above could be a cause.