Have sevice engine light on. Went to Autozone giving me code 0400. checked Google. Says its possible EGR Valve. Has anyone had this problem and replaced it and also could there be other issues with this code besides EGR valve. Autozone says could be gas cap, leak or some other type of exhaust problem. My Blazer is 97 4.3 v6 Vortec. Any suggestions before i spend the $100 on the part and replace it and not have that be the problem. Or will i be able to take it to a mechanic and pin point problem? without me doing a trial and error tell i fix it. Also vehicle is running find and smell no gas at all so dont think its a leak problem like Autozone suggest.

Thanks

 

EGr valve / flow malfunction. Nothing to do whatsoever with 'fuel'. Could be crud in the valve causing it to pass gases when it shouldnt, could be bad valve itself.


Why we always need the code.
NEVER let the AZ guy tell you what it is. He could be a really good mech.. or a complete idiot, like the one you had.

Remove the EGR valve assy from the intake. Cross fingers the gasket has a screen in it and it's plugged {that's what it's for}.
https://blazerforum.com/forum/articl...leaning-40424/

Determine the exhaust port. Should be the gunkier one.. if you cant, then plug one, then the other - with something solid enough not to be sucked in like it's a vacuum cleaner cuz that's what it's like - and start engine. Engine may not start with vac hole open.

You want the intake / vacuum side plugged.
STAND BACK.. all kindsa crap should blow out. If you have good loud puffing exhaust flow, it's the EGR valve. If it doesn't then the passage in the intake is plugged.

You can try to clean it, lotsa people do, or just get a new one. Get a new gasket with the screen.

 

Thanks I will try that!