Troubleshooting Mitsubishi Galant 99 rare behavior. What could be faulty?

Did you disconnect the battery? = Anti-theft system. You need to do a relearn procedure.

Or any of the things you did may have caused it.

Crankshaft timing slipped.

The new sensor is faulty.

Coils incorrectly connected.

I'm 99% certain it's all electronic if there is an arm it will be near the throttle body or around the throttle cable

I have a 4 cyl engine in my galant and the thermostat is found by following the LOWER radiator hose. You will need to remove the battery in order to gain access to the thermostat housing mounting bolts. There is a video on Youtube.com showing the removal and replacement of the thermostat and radiator for a 1999 mitsubishi galant.

http://youtu.be/Er1szRKrk7c

Mitsubishi Diamond Drive III ATF or synthetic equivalent ATF for the automatic transmission

Check here the Mitsubishi Galant Car Stereo.

Hope this help (remember rated and comment this).

usually all you need to do is hold the lock and unlock buttons at the same time for about 8-10 seconds will pointing at the car.

before you get into serious troubleshooting with your wallet i would suspect either a clogged fuel filter or a plugged catylitic converter.

Robert

its probably ign swich - located on end of ignition cylinder - round with 5 maybe 6 male terminals harness plugs into

try the following link--
http://www.ebooksquad.com/search/1999+mitsubishi+galant+fuse

temporarly disconnected the battery.