Ill try to keep this short and sweet... 94 lt1, m6. it has a low, surging idle sometimes dying. the fans come on 30 secs. after i start it and usually stay on. I had a tune done by pcm4less, its got long tubes, flowmaster muffler, new o2s, 30lb injectors, 1.6 rockers and cai. new temp. sensors, new opti, wires and plugs on it and still the same!!! it gets 21-22 on the highway but shiznit in town. I've owned these cars since they came out in 93 and never had one act up like this, any help with the surging/dying idle would help out a ton. oh how I loved my 93 speed density ta, no problems... (it was stolen... RIP)

 

First off hook it up to a scanner and look at the IAC counts. Could be a frozen IAC valve. Also sounds like What mine did when the fuel pressure regulator went. Pull the vacuum line off it and see if theres any fuel in that line. If there is you need a new one. If the fans coming on then you shuold have a check engine light. Scan it and give us the codes and we can help you a lot more.