Codes

I'm having trouble with my 1994 Nissan starting, it starts fine, idles up for a second or 2 then dies,after that I have to keep my foot on the gas to keep it running, 3.0 4X4 auto trans. There's no check engine lite lit, could there still be a code that would tell me ups with this. Or what do you guys think it is?
Thanks
Joe

I'd suspect you have a vacuum leak.

-Rod

I check the ECU and came up a code 55 witch means no malfunctions. Checking the code I would turn the key on, then turn screw fully clockwise, wait and the red and green light would blink 2 times and then it would blink 3 times, at that point I turn the screw fully counter clockwise. Then I got 5 red flashes and 5 green. Did I do this correctly?
Thanks
Joe