I just bought a 91 RS with th 5.0. It drove home great. I cleaned the engine and it still ran good for a Short time afterwards. No it is extremely hard to start and does not run good. I get a strong smell of gas and when it runs it idles high. Sometimes it sounds like it has a bad vaccum leak then it stalls.

Any suggestions ????

 

Welcome aboard thirdgen.org.

Is the SES light coming on while the engine is running?

First thought is you got water in an electrical connector. Perhaps start by disconnecting all underhood electrical connectors (one-by-one) and dry them out.