Originally Posted by Captain Hook

CSFI is fully OBDII compliant, CPI is not. CPI doesn't have the capability to control the banks seperately due to only having one injector, and one upstream oxygen sensor, (one big bank). One of the requirements to be compliant with OBDII, is if the engine has more than 4 cylinders, it has to be able to control both banks individually. In order for GM to produce the 4.3L in 96, they had to redesign it to CSFI.

Early 95 production was OBDI. Mid year production was affectionately referred to as "OBD1.5", (a step toward OBDII). It has the OBDII port under the dash, but uses a unique protocol for communication that not all scanners can communicate with. From what I have read in GM publications, and heard from friends at GM, they ran out of OBD1.5 engines, and the CSFI was ready to go, so they used it at the end of the production year. No clue how many were installed though. Over the years here on BF, I remember 1 for sure, and possibly 2 members that had 95's with CSFI. From the VIN that one of the members gave me, it was in fact a 95, and it had CSFI. I'd LOVE to see one, might even be worth more $ for being so rare. Although not as rare as a 95 Bravada!