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Q: New IAC Valve - High Idling but old IAC Valve normal (800/900 rpms) 1993 Saab

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Good Day,

2 Questions please

  1. I replaced my IAC valve with a new one purchased online. However, the new IAC valve idles at 2000 - 2100 and even when it comes down it comes down much later in the day and still seems high at 1100.

But the old IAC valve starts high and comes down to around 800 - 900 rpms. This one seems fine. -------There doesn't seem to be a vacuum like anywhere.

Should I just leave the old one or have I found more problems with the car?

  1. If I have a fuel pressure regulator problem - would the "ENGINE" light come on?

additional info--Car takes 3 - 4 tries before it starts, which is why I tried putting a new IAC valve. I just installed a new MAF sensor. Still cranks after 4 tries when it's cold.. I think it's the FPR.

Thx a bunch... Shafi
My car has an automatic transmission.

Hello - I think you were on the right track with the idle air control valve. It sounds like your engine is getting extra air from an intake leak somewhere. It’s also possible there is a throttle body problem. The "multiple tries to start" problem sound like the fuel pump check valve bleeding down overnight. The fuel pump has to work extra long on first startup each day to compensate for no residual fuel rail pressure. Putting a fuel gauge on the fuel rail will confirm/reject this possibility. For diagnostic assistance, I recommend a high idle inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.

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