merchauser

factory spec says my car should idle at 775 rpm.

to my ear and feel, the car idles spot on, with no detectable idle problem or issue.
"feels" smooth as silk, and tach needle is steady. but when hooked up to the hammer,
the reading fluctuates between 795 and 848; not an immediate rapid jump, but every few seconds.

is this normal, or should I get a dead on consistent 775 reading? if this is a problem, what could
be possible problem(s)?

Mrmerlin

How much have you driven this car?
Have you been using techron every 3K miles and using MMO and Startron in the fuel?
How many miles does it have?
When was the last intake refresh done,
Did you replace the fuel injectors?
Did the idle stabilizer valve get replaced?
Has the car been stored in a climate controlled low humidity environment?
Is this an auto or stick?

merchauser

I drive this car a few times a week and like to run it thru its gears manual
I use non ethanol 90 octane gas
84k on the odo
intake has never been done
original injectors
original ISV
stored in climate controlled garage

the main thing is that I do not feel or notice any issues and have no complaints
not saying that there are things that do not need tending to

should the hammer idle reading be dead on steady at 775?

siscogts

Bear in mind that ecu has to work with your Hammer and the engine at the same time, so it is normal you will get bad idle when you're working in fuel injection and idle.

The Forgotten On

If your 928 has a 02 sensor that fluctuation sounds pretty normal. If it is smooth to you it is fine, the idle isn't that high or out of spec enough to warrant concern.

Mrmerlin

best thing to do for any idle issues is to add techron every 3k miles and add 6 oz of MMO and 2 oz of Startron to every tank,
this will keep the fuel injection system clean and reduce ethanol issues