Ford Repair: clarify the problem, vacuum gauge, mercury topaz

Question
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Followup To
Question -
I have 1991 Mercury Topaz showing service engine light often.which comes up code 33,canister or EGR valve not operating properly.Ichecked all vacuum lines,they are ok.Ineed infromation and troubleshooting help.Thanks.

Answer -
more information needed.....engine size, auto or standard transmission, AC or not, ANY driveability problems noticed.
Erik

More infromation,2.3 automatic with a/c.Driving on the highway is ok,but around town engine light comes on and idle drops down at stop light and often dies.  

Answer
Hello and thanks for the reply...I'll try to help.
I've looked in to the code 33 hat you are getting and it is for the EGR vlave opening not being detected. To further diagnose this I would suggest that you attempt to perform an key on engine running test and verify the vacuum signal to the EGR valve during the test. To do this enter the running test and remove the vacuum line to the EGR valve and install a vacuum gauge in it's place. At some point during the test, you'll notice that the gauge will increase from 0 to upwards of 20. If not.....you have a EGR signal problem. If it does increase......I would remove the EGR and make sure that it isn't "stuck" in the closed position. Also, make sure that it will hold a vacuum by apply vacuum to it and that it doesn't leak.
hope this helps,
Erik