Yup, here I am. The Rodeo and Axiom V6's were all direct injected in the last 10 months or so of production. By that time the Trooper was gone and had been 'replaced' by the Trailblazer based Ascender which used the 4200 GM I6 and V8's.
At the time, only Isuzu and Mercedes offered direct gasoline injection in the US market. Those Rodeo/Axiom engines were completely designed and engineered by Isuzu, they had no GM connection at all. The basic engine architecture first came here in 1992 with the Trooper in both SOHC and DOHC forms, in 1993 Isuzu began using a variant of the SOHC in the Rodeo. Isuzu also designed the Duramax diesel for GM, in truth it's an Isuzu engine.
The DI motors were based on the DOHC version which had big cylinder head design changes in 1998. DI was good for around a 20HP increase, I don't remember the torque figure but along with that power increase came a roughly 12% jump in gas mileage. Then GM finished pulling the plug on AIMI (Isuzu's North American operations) and the rest is history.
The very first 1992-1993 V6's had a reputation for oil leaks which was fixed for '94, the 1998-2000 DOHC motors had PCV systems which could lead to heavy oil consumption if not maintained regularly. That was changed for the '01 model year, those are tough and reliable motors. Even the '98-00 are tough as nails if you keep after the oil changes and PCV valve replacements.
