runaway idle

95 intermittent idle problem ...gradually gets higher on highway up to 2500 rpm....braking becomes impossible. put in neutral..rpms go nuts..up to red line shut off...restart rpms up to 2500,,,revving to redline & 2500...cat conv red hot...smoking.

let cool down for 1/2 hr restarts ok...sometimes.

have replaced fpr,plugs,wires,egr valve,pcv valve, fuel pressure sensor.

any ideas? hard to restart sometimes..long cranking.

Hard starts = Fuel Pressure Regulator (common problem)

Also your cat is clogged, get it replaced. High flow is nice, probably cheaper then the OEM replacement. And you will get more exhaust kick ;)

I would also get your Idle postitioning sensors and TPS checked out.

Braking becomes impossible? how?

Sounds like your car needs a bit of TLC right now