Tech Support Forum - View Single Post - 1991 chevy s10 blazer 4.3 engine backfires in intake manifold

**Raylo** · 05-29-2008, 04:43 PM

Sounds like a stuck open EGR valve. It runs good at high loads because that's when the EGR is open most normally. The EGR should close as the load comes off and be shut at idle.

05-29-2008, 04:43 PM	#2 (permalink)
Raylo TSF Enthusiast Join Date: Feb 2006 Location: Maryland, USA Posts: 525 OS: XP Desktop, Vista HP Notebook, XP Notebook	Re: 1991 chevy s10 blazer 4.3 engine backfires in intake manifold Sounds like a stuck open EGR valve. It runs good at high loads because that's when the EGR is open most normally. The EGR should close as the load comes off and be shut at idle.