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1992 GMC Sonoma 2WD

I have a 1992 GMC Sonoma pick-up truck 2Wd rear drive with 6 cylinder 4.3L engine.My question is how to find out whether this engine is single port fuel injected(SPFI) or multiport fuel injected(MPFI).Don’t have Vehicle manual.

Your 92 Sonoma probably uses TBI (Throttle Body Injection) the main part looks like a carburetor and contains 2 fuel injectors.

The S in SPFI stands for sequencial fuel injection (lose the “P”)

There is a designation called “grouped single-fire port injection” and its class designation is MPI (Multiport injection)

Then there is the famous CPI or CMFI (central multiport fuel injection)which uses 1 injector and 6 poppet valves,perhaps this is what you are thinking of.

There is no system that I would call single port fuel injection. I guess a one cylinder fuel injected engine would qualify.