there were a few incidents when my tach doesn't move at all after a cold start. but it always worked fine again after a few minutes. when this happens, the battery indicator on my dash lights up as well and turns off at the same time as the tach 're-functions'. this only happened a few times before yesterday. but from last night and today, its always happening when i start it up. and the last time, it didn't go away. (the battery is less than a year old by the way).

and this happened after i finally fixed my idling problems!

any ideas?

 

Your alternator is toast. The battery light being on means that the battery is being drained, the tach not working means the alternator is not putting out.
The tach runs of the alternator. 30 min job to replace it.

 

X2, I think Autozone carries one with a good warranty on it...

 

i assumed it was the alternator. ill have it tested 2morow. the weird thing is i drove it just now and it ran ran perfectly. is there any chance that its just sum loose wiring or sumthin?

 

Did you have the serpentine belt off recently? I've heard of the alternator slipping if the belt is routed wrong since the wrong routing significantly reduces the contact patch on the alt. pulley. It would be more likely to slip when cold-the belt would get more grip as it heats up...

 

Yes it could be a lose wire on the back of the alt. Pop the cover off and wiggle the wires. Tighten as needed.