I need a vacuum diagram and ECU help. on 1991 Nissan Maxima

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I believe I have a vacuum leak but I can't find one and i don't have a vacuum diagram. I ran a diagnostic on my ECU and got the codes 33 and 51. What do they mean wnd how can I fix them? My check engine light is also on. The car idles high and the RPMs bounce between 1500 1nd 2000 while idling but other than that the car runs great. Ang suggestions or answers are appreciated. Thanks.
(1) Answer
(1) Comments
Code 33 is for the EGR System, so check that it is functioning properly.
Code 51 is due to an open in the injector circuit. Make sure the connectors to the injector(s) are OK, and that the injector wiring is OK.
I don't have a vacuum diagram, but if you think there is a vacuum leak, try to locate it by listening for hissing noise around the hoses and intake manifold. Visually inspect all the hoses and the intake piping.
actually 33 is oxygen sensor fault, 32 is EGR fault