engines missfires aft 3000 rpm and no power

[angelo1952]

I have a 1978 fiat 124 spider with dual 40 on with european manifold about a month ago in heavy traffic and running slightly above normal temp it start missing and loss of power above 3000 rpm got the car home let it stay overnight started right up and no further problem the next day and it has been running fine ever since. The other day we again got stuck in a little traffic same scenario and starting loosing power and sputterring at 3k+ rpm but no problem below that range, I have checked points and ok, checked plug wires and seem ok and also replaced spark plugs ran fine for a little as soon as I got on the fwy and reached temp it started loosing power and sputtering above 3k but hold idle fine. Is it carburation or Electrical and what should I check next. Thank you very much for your help

ps I have also changed it back to a single point set up and running 10btc

[puddin]

always wondered why fiat's didn't have ballast resistors-- my 78's ig coil would get screaming hot and do the same thing-- bought a new coil and ballast resistor -- no problems since and even on a cold day it fires just fine.

[seabeelt]

How is your fuel pressure?? Electric or manual fuel pump??

[angelo1952]

I have not checked the fuek pressure but it isamechanical fuel pump

[mdrburchette]

A mechanical pump could cause an intermittent problem, especially at higher rpms or under load. It will eventually just quit pumping fuel.