Scan it for codes and post your results.
It is nearly impossible to diagnose a vehicle without seeing it or without codes.
When running and ac and everythings on and its real hot out side.At a stop light the car will die but start right back up.I think its some sort of vacuum problem did tune up vacuum lines,water pump,fuel filter.Trying to help a friend out in North Carolina fix his car don't know much about 8v mk3 any help will do thanks.
do you have any battery/alternator issues or charging issues of any kind? sounds like the extra drag caused from your a/c compressor kicking on may be putting strain on yourt alternator....just a theory
Last edited by jiffyjetta; 08-06-2012 at 07:01 PM.
if its obd2 then there is a signal wire that tells the ECU that the A/C is on so it can bump open the throttle a bit. if its obd1 then there is an IAC valve that does the same thing as the throttle. Id get my bentley out and tell you exactly what wire it is but its not handy. Does your AC work when your car is off idle? like higher than 1000 rpm? also post what year your car is.