I have a 98 Z28 with a newly installed 366 cu in engine. The engine has less than 7k miles on it. Lately when I try to start it 80% of the time it gives me a hard time. The idle goes up and down, so low it just cuts off. When I try to restart it sometimes it sounds a little like it won't turn over but it does and it idles low again until it shuts off. It also smells pretty gassy. Usually I have to give it a little gas for a little while until it stops idling low enough to turn off. Any suggestions?

Problem #2
When I run my A/C the transmission doesn't seem to shift right and I can't seem to turn off the ASR.

Someone suggested a TPS to me. Any help would be appreciated.

Thanks