saturday on the way to the show i was just cruisin along and all of a sudden my car just starts bogging down and the check engine light turns starts flashing rappidly,not shutting off.so i stopped and the lights start flickering and the motor sounds like it's going to shut off,goes to about 400rpm then shoots up to about 1500rpm and back down about 4 times then idles fine.Since than any accesory like electric fan,any lights, it effects the idle of the engine and all the lights dim,i think something like a connection is loose,i can;t keep the check engine light on long enough to get a code because it only turns on when iput a load on it.any help or suggestions would be appreciated,thanks in advance.

 

alt. is bad

 

alt. only 2 weeks old,ran an alternator test and battery test and all good.maybe it's a bad connection?the car sat for 2 1/2 years so there might be some corrosion.