Rough idle on my '95 Chevy S10

[TPringle]

The other day my '95 S10 developed a rough idle and surges when driving. Started fine, drove it a few miles, and stopped, then noticed the problem. It sounds the way an engine with a stuck choke or bad float sounds. It does smell rich. The engine is the 4. 3 Vortec V6 with the center fuel injection (under the manifold). This is not the TBI injection engine. I am still driving it to work, but fear it cold lay down on me at any time. The engine light came on, and I get a P1406 code, but havent been able to find any definition for this one. Wonder if this could be the pressure regulator. Anyone out there had this problem?

 

[JLEONARD]

This might not apply, but when I had this enigne with the throttle body injection, I got a rough idle because the gasket at the base of the TB failed and the engine was sucking air. It was easy to diagnose with carb cleaner spray and easy to fix.