(This is cross-posted to the Vortex)

Last night I had the battery disconnected for a while to
reinstall an amp. After finishing and getting everything
back together, I started the engine and everything was
fine. This morning however ... different story. The idle
started bouncing between about 400 and 800 RPM as soon as
I got backed out of the driveway. This condition kept up
all the way to work, except that every now and then it
would bounce all the way to about 1000 and when it did
that it'd settle back to 700 and idle perfectly. As soon
as I gave it some gas and let the revs drop it would start
bouncing again. When I got to work I started and stopped
the engine a couple of times, but it idled the same. No
CEL.

Could this have had something to do with the battery being
disconnected? I've had it disconnected before for whatever
reason and it's not caused this behavior. Does the car
have to learn how to idle or something?

Car:
98 GTI VR6, 58863 miles, 1/2 tank gas BP 93, new Bosch
plugs at 30K

Relevant Mods:
GIAC chip at 24K, K&N drop-in at 6K cleaned at 50K

Any ideas greatly appreciated!


matt.

If u have the giac chip installed and u disconnect the battery you will
experience rough idle.  Just like when you put the chip in the first time.
In disconnecting the battery you are in fact resetting the computer (ecu)
and it will take a minute for the rough idle to go away as the ecu, chip and
system readjust.

Disconnect the battery again.  Let sit for a few minutes.  Reconnect.  Start
the car and DO NOT TOUCH THE GAS.  Let the car idle for 5-10 minutes.  It
should then relearn the idle settings.  Uwe gave me these instructions when
I installed my chip and it worked for me.

m-