svptwobe

I got a the check engine light on my 1991 LS400 and the code is "71", which is a EGR System Malfunction. The car will all of the sudden idle real rough and then go back to normal. I read where the EGR gasket causes this. I have changed the EGR valve gasket and cleaned the HELL out of the EGR valve. The car is still running rough. Anyone had this problem and what was the fix?

svptwobe

I did the following to relieve the problem.

1) I took the EGR valve off and cleaned the HECK out of it.
(2 - 12mm nuts). I used (WD40) and a small wire brush
to clean it. I also made sure the diaphram could move up and
down.

2) I took the mounting bracket the held the EGR valve (2 - 12 mm
nuts and 2 - 12mm bolts). This bracket has a temp sensor on
the bottom. I also cleaned the heck out of this.

3) Bought gasket material to make new gaskets for the EGR valve
and the bracket.

4) I also found that the air duct hose from the air filter was
cracked. I used black duct tape to fix for now until I find generic
air duct hose.

5) Disconnected battery terminal for 1 minute to reset ECU and
clear check engine light.

Car is running great for the past 3 days and no check engine light.