Toyota Repair: EGR Cleaning, vacuum hose, machine screw

Question
QUESTION: Hello Ted!

I have isolated the EGR valve by disconnecting the vacuum so that I know the valve is not closing which makes the car idle rough. I have some questions about cleaning it. The car is a 1995 Camry LE 4 cyl with air conditioning. The EGR valve is connected to the intake on the passenger compartment firewall side of the motor. My car will not pass inspection since it does not idle with the EGR valve connected and I don’t want to spend $400 to replace the valve.

When I remove the exhaust gas metal tube from the bottom of the EGR valve, do I need to heat the nut to remove it or can I just spray WD40 to successfully remove the nut?

Should I spray carb cleaner or throttle body cleaner into the valve?

When I spray cleaner into the part that bolts onto the intake and the bottom of the valve with the valve closed, should I let it air dry or use light air from an air compressor to dry it out?

Do I stick some type of brush into the valve?

How much vacuum should I apply to the valve so I can spray cleaner on the pinot valve?

How do I know that I have successfully cleaned the valve before reinstalling it to the intake?

Am I missing something that will aid me to successfully clean the EGR valve?

Many thanks Ted!

Sincerely,

Mike


ANSWER: I'm not so sure that the egr valve is the problem since they almost never fail, before going on I need to know if the vacuum hose to the egr valve is connected does the engine die or stall, with the vacuum hose disconnected does it then idle normally?

---------- FOLLOW-UP ----------

QUESTION: Hi Ted,

When the vacuum hose is connected to the EGR valve, the engine does not idle smoothly after warming up. I need to depress the gas pedal and ride the brake at low speeds or put car in neutral and tach it up to 1K when the EGR valve is connected.

I have been running the car without the vac hose connected to the EGR with  a machine screw in the vac hose for a few months now. The car idles smoothly and never tries to stall.

Once in a while I do get a low idle of just under 750 rpm, but that is rare. The car idles normally decelerating and idles normally at stop signs with the EGR valve disconnected.

Thanks Ted

Sincerely,

Mike

Answer
The egr valve should not get vacuum from the hose at idle, only at cruising speeds, somehow there is vacuum being applied to the egr valve at idle, check the vacuum diagram on the label under the hood, there may be some vacuum hoses mixed up. If the egr valve was staying open then it wouldn't make any difference whether the hose is on or off.