Hello group,
148k miles, the car is idling erratic from normal, but consistent. Comes to a stop and it revs up to about 1750 for a short time and then drops down to about 900, rough idle, check engine light.I checked the vacuum pressure by tee'ing in the vacuum line between the PCV valve and the throttle body, the reading on the guage came in at 15 PSI @1000 RPMs, but not sure what it should be.
I looked in the haynes and chilton manuals but could not find any manifold pressure spec listed. Does anyone what the vacuum should be at 1000 RPMs for this car?
I can hear a hissing sound near the firewall, but so far have not been able to find an open vacuum line. It might be coming from inside the air bypass valve, not sure, maybe need a stethoscope. I tried listening to egr valve with a spare vacuum line, but did not hear any vacuum hiss.
Any ideas, TPS, EGR, air bypass solenoid, O2? Getting a KOEO 41.
Thanks, Matt