Hey everyone, i have a 1991 4runner. Picked it up around 4 months ago. I decided to install a new muffeler being a flowmaster 44. About 50 miles after intalling the muffler it through a check engine light. Im reading code 71. Im not sure if its something to do with the exhaust or maybe just a coincidence? It runs fine its just the cel bothering me. Any further notice

Gavin

 

What IS code 71? Did you expect that every other member of this forum had memorized all 20 of them? Since you figured out how to read the code, the same reference probably told you what it meant.

http://web.archive.org/web/201211190...85diagnosi.pdf

 

Scope103 code 71 means egr system. I tested the egr system by using suction directly to the vacuum line on the evr valve. It seems to be working fine. Next I replaced vacuum lines becausw i noticed they were cracked. Thought that would have been the problem for sure. Throws the Cel again. At this point im wondering if the egr system has anything ti do with my exaust because if so i will need to get it replaced. Need to get smogged but the stupid light is setting me back. Im fairly new to this engine being the 3.0 v6

 

I assume your test of "the egr system" was just to put vacuum directly to the EGR valve, and noticed engine stumble. That's good, but it's only step #6 in the diagnostics.
http://web.archive.org/web/201003261...77exhaustg.pdf

The EGR valve puts exhaust gas into the intake plenum, so if you get the stumble with your limited test your problem is probably not on the exhaust side. Instead, you'll need to test the vacuum that comes through your new hoses (a gauge is the right way to do it, but since you're only looking for go/no-go your thumb will probably work). Then you'll need to move onto the EGR modulator and the VSV.

The manual (cited above) gives you what you need to know.

 

Thankyou! Will look through and take the proper precautions.