No power

I have a 1997 305
At first startup there is no power. Idles reasonably well with a small shudder but when I drive I can only get about 30 mph out of it.
After approx. 5 min it clears up and runs pretty well. I've done both intake gaskets, plugs, rotor ,wires, 4 O2 sensors. Fuel pump was done about 18 months ago. Fuel pressure is about 59 psi at idle.
Getting frustrated and any help would be appreciated. Thanks

what about the catalatic convertor ?? or muffler ?? sounds like could be stopped up or comming apart it sounds weird but your problems i see a couple of possibilities cat convertor, muffler or what about a fuel filter....TRUST ME ANYTHING IS POSSIBLE !!!!

what about the catalatic convertor ?? or muffler ?? sounds like could be stopped up or comming apart it sounds weird but your problems i see a couple of possibilities cat convertor, muffler or what about a fuel filter....TRUST ME ANYTHING IS POSSIBLE !!!!


I don't think it is the muffler or cat as there is lots of exhaust. Thanks

If it runs well when warmed up, then perhaps something is telling your computer that it's warm when it's actually cold. Something such as your coolant temperature sensor.