I have a 99 galant which has an rpm needle problem. on 1999 Mitsubishi Galant

I just had my timing belt and crankshaft sensor replaced. Car runs fine but once i turn on the heater the cars rpm/idle needle starts moving uncontrollably and the car start to misfire by shaking and not wanting to accellerate. The check engine light also goes on but i had the light check and it says it needs a tuneup which i already did with new parts. I dont know what to do.

by in Brooklyn, NY on December 28, 2011
2 answers 3 comments
ANSWER by on December 28, 2011
you need to resolve the light issue which is telling you about a missfire. start with a compression test to see if there is any valve damage. Roy
COMMENT by on December 28, 2011
the check engine light appears once the rpm/idling gauge starts to spin uncontrollably. Once that occurs the car begins to lose power, shake and not want to acccellerate. I also change both coils.
ANSWER by on December 30, 2011
I want to make sure I understand.....the engine misfires only when you turn on the heater?......or the misfire becomes worst when you turn on the heat?
COMMENT by on December 30, 2011
The engine starts to misfire only when i turn on the heater. It is very weird.
COMMENT by on December 31, 2011
A diagnostic is needed to resolve the problem........has anyone replaced the radio or installed alarm, made any changes electronically?