I have a 1990beretta that starts and idles somewhat rough but will stall if you touch the throttle. Have replaced the fuel filter, plugs and wires, swapped out the map and tps with no change. Codes have been checked and nothing was stored.
Any ideas?

 

Changed the coil pack and it no longer stalls but still won't revup properly.
I'm thinking a weak fuel pump?

 

Changed the fuel pump and still runs the same.

 

What motor? could be ignition module...

 

It's a 3.1L, the entire coil pack has been replaced and (as far as I know) the module as well.
I'll have to check it actually belongs to a friend and I'm not 100% about the module.

 

Ign module sits underneather the coils and is a separate unit.

 

Yes, the entire coil pack and module were swapped out, this helped somewhat as one of the original coils was weak or intermittent.
However the stalling problem still exists. Also removed the O2 sensor from the manifold temporarily to check if the catalytic was plugged, again no change in the stalling problem. TPS and MAP have also been swapped out.
The next step will be to replace the Crank sensor unless someone else has a better idea.

 

I think you're on the right track

 

Have you been running any ethanol? I have had the same problem with a Cutlass. It turned out one of the injectors was borderline bad and caused this problem. Do you have a scanner of anysort to check the O2 readings while it is running?

 

Well we changed out the crank sensor and still no change. Just regular fuel but we are now suspecting the injectors, unfortunately we don't have a scanner that will monitor while running.
Thanks for the comments.