1993 ecm has a short or is loose

I have a 1993 corvette and have what appears to be a loose ecm or a short in it. When I tap on it, it changes the idle and might even shut the car down, other times when I tap on it, it clears up my problem for awhile. The problem: Service ASR and service engine soon indicators come on intermittently. When there on none of these work: my cruise , odometer, speedometer, MPG, I get no cold air and passing gear power is not there. When I tap on the ECM and they go off everything goes back to working just fine. Could something just need tightened, or could a conector be bad? I can't realy afford a new ECM and I have been told at the dealer that is what I need. But I question this. PLEASE HELP HERE! Reply to me at: prowantexotics@yahoo.com  

time to open the ecm...   examine it closely...     see if there are any loose items...  things that plug into the boards...

examine the solder connections..     i have repaired many electronic modules with a soldering iron...  my former boss thought i was a *** i fixed his old corolla..  he did not even know it had a computer in it...    took my half an hour after i got it out...   i have spent 3 hours on some ecms...  redid almost every solder connection...  but that was a really expensive ecm out of a benz...  

look for tiny rings in the solder connections...  

what happens...  the wire gets hot... the solder around the wire expands... the solder that is in contact with the circuit board has more area to spread the heat out too..  

this thermal cycling expands the center of the solder joint... solder is not that flexible ...  so the inside pushes out... expanding and contracting until the joint breaks ... leaving a visible crack in the solder joint...

this has been a fault in electronics for years... and is going to get really really bad with surface mount devices...  i have to redo them a lot in lap tops...  the power supply boards are notorious for failures... but wait... lets get back to the corvette problem..

only one thing...  you have to be sure to NOT blow things out...  many of the circuits are CMOS....  14 volts will smoke them...  they run at 5 volts...

above 10 volts the circuits are so close internally... the increased voltage can arc across inside and blow out the device...   but there's no power attached...

ever hear of static????   same stuff that ignited the hindenburg fire..

you can have thousands of volts of static voltage on your body..   buy a ground strap from radio shack...    attach it to the chassis ground ... figure out what is the ground first... i saw a guy blow up a computer board... he hooked his ground strap to the power side...  

got any VCR repair shops near by????    got any computer repair guys..  professional recording studio techs?????  many of them know how to repair circuit boards...