EGR solved - '94 Camry 4 cyl.

[Daniel M. Dreifus]

EGR solved - '94 Camry 4 cyl.

Add to my prior posting about cleaning the EGR valve and replacing the vacuum switching valve with hinged head ratchet handle and wobble extension.
Also needed to change the Vacuum Modulator. Right next to the EGR valve. Very easy to just pull the vacuum lines and replace.
Tested the old by blowing through one line, holding the other two closed as in the FSM. Air did not flow freely. New one didn't seem much different, but check engine light is gone and pinging is gone, plus fuel mileage is back up.
Seems that vacuum modulator cycles constantly at low throttle, opening and closing to atmosphere and EGR vacuum in a constant feed back loop.
My guess is that because the VSV and EGR Vacuum Modulator both have air filters, after 193,000 miles, somehow the operation of these valves becomes impaired.
So, all good now.

Also note: from prior post about cleaning EGR port in throttle body with a wire. After removing the EGR valve for more thorough cleaning, the passages did seem unrestricted just from cleaning without disassembly through the TB. I was able to do a more thorough job with the EGR valve off, but looked like it was already fairly well unrestricted. Once the TB was off, really wasn't too much to R&R the EGR though. Just needed another new TB gasket. BTW union nut is 15/16"