EGR code won't reset. Newbie blues.

2001 Tacoma 2.7 3RZ won't clear EGR to test for smog. Engine only has 140k, but it's an OEM replacement. Odometer reads 386k. At this point she's a grandma, that performs like a workhorse.

I know this question has been answered many times in the threads, so please bear with me. This long winded message is really just trying to clarify one thing.

Here's what I've done so far:

Replaced the EGR valve, the diaphragm next to it and the EGR housing (it has a different name I can't remember) on the battery side of the engine compartment. Check engine light led me to the EGR codes. I'm about $900 in for parts and labor at this point. No more check engine lights, but I've got that old smog problem. Neither my smog tech or my trusted mechanic (both running Zeus diagnostic systems) can get the EGR to clear for smog qualification.

Somewhere in these threads, I read the culprit may be a blocked exhaust vacuum hose. That part I understand. But is there more than just a vacuum hose that needs to be thoroughly reamed?

In other words, one of the threads mentioned that I need to "chisel" the crud out.

What exactly am I chiseling?

My mechanic did the flow test by attaching the vacuum pressure gauge to the EGR and the engine rpms changed drastically. His argument is there is nothing else to clean if the vacuum gauge changes the RPMs. These threads seem to elude to something different. Don't really want to go the "referee route."

Tried all the start, idle till warm, drive between 43-56MPH, let idle, repeat stuff. Done it the last four days and have logged over 300 miles. The good news is no new check engine codes, but it's still not clearing EGR.

Suggestions would be appreciated. I'm new here, so forgive me if I've done this the wrong way.

Thanks.

 

Try a scan gauge or battery disconnect?
All new fuses
Worth a shot

 

It's not a hose but a metal pipe from the exhaust to EGR valve. Remove it and soak in parts cleaner then dig out deposits as best you can.

 

Welcome to TW!

 

It’s all just trial and error. Nothing wrong with that and soon we all become experts after lost of that