Postby manga_blue » Mon Nov 12, 2018 12:16 pm
OK, you keep getting a fault code for a vacuum leak. Is that correct?
Just working from first principles I'd say that means it is registering low vacuum at idle. I'd just tap a manifold vacuum gauge into the manifold somewhere.
If it really is low then keep unplugging and blocking off vacuum hoses on the manifold until something noticeable happens with the vacuum reading. It may be a leaking hose or a leaking device. Brake booster vacuum, fuel pressure relief valve, EGR valve, blow-off valve, carbon canister, MAP sensor, cruise control unit, PCV valve are all candidates that spring to mind.
If the vacuum gauge reads fine then maybe whatever sensor feeds the ECU (probably the MAP) is dodgy.
If you get nothing out of that lot and you're well down on power then I'm afraid it's time to check engine compression and to look for an exhaust system blockage.
’95 NA8