help me fix this idle gremlin
 

I used to have the accelerated warm up until the valve on the uim, next to the intercooler, and behind the bac valve broke so I just bypassed it straight from the uim manifold nipple to the interooler pipe.

Anyway, I start the car up after it sits over night and fires up to 500 rpms, slowly rising to maybe 700 for a second then it starts to drop, maybe die if I don't gas it up to keep it idling. I'd like to get it to idle right without dying so I can start the car up to warm it up while I am getting ready to leave.

On a side note, I have some bad voltage ...13.8/13.9 at idle, then to 13.6 after the car warms up. This is with no accessories on. The alternator is a rewired s5 model. Battery is new. I have just replaced because the other battery died after half a year of use. If I get below 750 rpms with some accessories like the a/c or if I am using the brakes, the car will lose voltage and want to die. These readings are coming from the greddy turbo timer, which seems to read lower sometimes than direct voltage reading from the battery. If the turbo timer is seeing less voltage than actual voltage, and the turbo timer reads the ecu, could the ecu also be seeing this low voltage and want to die? ...seems like a problem in the ecu or wiring maybe?

edit - the car also occasionally takes 3 key turns before the starter initiates.

Either way, this is an old on going problem I have just usually delt with. Another one is hesitation/stuttering when the car get's around 13.4 volts or lower. I wanna say it has something to do with the ecu reading this low voltage and it effects my ignition, timing, fuel pump, etc.

Any input? I plan on taking it to a rotary doctor anyway, because I am tired of trying to solve this gremlin. But, I am willing to take a final stab at it.

bump

For the idle problem, do a check of the mechanical idle setting per the FSM for your car...

For the voltage thing, check it at the batt terminals, and check it at the alt (top terminal post to alt body). If there's much more than a .1 volt difference between the two, your wiring and connections/ terminations need checked...

If you don't read at least 14.4v at the alt with the rpms at about 1000, suspect the alt...

Voltage will fall a bit as the alt heats up, that's normal...

The other problem sounds like an ignition switch or starter solenoid, or the wiring connections at the starter...

Check your main grounds, also, especially if the readings at the alt are good...