86 944na: what's normal for the MPG gauge..?
Must be a vacuum leak, the gauge slowly fluctuates between 29-31 at idle when engine is hot. What's normal at idle? I would expect it to be rock steady. I read a previous post that said his was 50!
When cold, the idle RPM is goes low, almost dies, about 300, then surges to 2000, then back down again to 300.
I sprayed all the vacuum lines with carb cleaner, but unable to locate any leaking hoses/connectors. I do hear a faint hiss from somewhere in the top center intake area when the engine surges, then hissing stops when rpms lower... is this normal?
After warmup, RPM is about 1500.
Sorry for the ramble... just replaced cap,rotor, wires, plugs, fuel filter, air filter which improved this condition but didn't fix it. Exhaust is tight, no leaks, car is stock. I'm thinking next idle control valve and o2 sensor. Is it true the o2 sensor only is activated when hot?
Any ideas? Yes, I already did a search for previous posts. Many many thanks
BOB
86 944na
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