Car boggs down far........

[iwashmycar]

I started up my 90 GT 5-speed and I let it idle a minute and it almost reached to point of dying on me. The RPMs would go up and down, but stay really low. I ended up givin it gas and it was ok.

The bigger problem is my bros car.....
Its a 94 GT auto, and sometimes dies, and very frequently boggs way down when he shifts into reverse. Sometimes it does it shifting from reverse to drive too.

Anyone have these problems before?
What could it be?

Thanks for the help!

 

[HISSIN50]

have either of you pulled codes? there are several things it could be (cold-enrichening functions, IAC, etc). codes or lackthereof might help people diagnose what gives.
good luck.