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

**Raylo** · 06-02-2008, 09:42 AM

That's different from mine, which has no vacuum lines. It apparently uses a small electric stepper motor. So you might have a code Z motor?

Anyway, the only obvious things I can think of to cause backfire are egr, swapped spark plug leads, or timing way off, as in a slipped timing chain. But all of these things should be noticeable at idle. Sorry, without more info I can't help.

Good luck.

06-02-2008, 09:42 AM	#9 (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 That's different from mine, which has no vacuum lines. It apparently uses a small electric stepper motor. So you might have a code Z motor? Anyway, the only obvious things I can think of to cause backfire are egr, swapped spark plug leads, or timing way off, as in a slipped timing chain. But all of these things should be noticeable at idle. Sorry, without more info I can't help. Good luck. Last edited by Raylo; 06-02-2008 at 09:45 AM.