I have 90 v6 camry and I consistently fail emissions (NOx) - my questons: When I clean the intake port that mates with the EGR valve do I need to be concerned about damaging any sensors that may be in there? Also, should the port, when cleaned, be the same diameter as the port on the EGR valve? Most Gracious

It's best to take off the throttle body to clean EGR gas passages.

danielsatur - isn't removing the throttle body a sensitive procedure? aren't there adjustments that i need to be concerned about?

Throttle body removal is pretty straightforward. There are no sensors other than the throttle position sensor that are mounted to the TB and as long as it stays attached and the linkage adjustments are not disturbed, there is no worries when reinstalling it.

The EGR valve is a vacuum-controlled valve only, there are no sensors inside of it. There is only a vacuum diaphragm. If it has a hole in it then it won't hold the valve open when needed. It can be tested in place with a hand vacuum pump...if it holds vacuum then the diaphragm is good. If the valve fails to open or close then the mechanism is stuck due to deposits. These can be cleaned with the valve removed using carb cleaner and a pipe cleaner to scrub away deposits.

Hope this helps!

Thanks for help, it's always good to have a 2nd opion, and set of eyes.

Thanks all - i've been dealing with failed emissions for the past few years -- I'll clean the throttle body and replace the O2 sensor - I see an O2 sensor when I look thru the wheel well on the passenger side -- is there more than 1 O2 sensor on the 1990 v6?