I have a all-original(that is, no modifications or "modern" upgrades anywhere on the car) 1967 Duetto 1600. It was running near-perfectly until 6 months ago, when the idle became low/rough/erratic. It normalized when the car was fully warmed up and never actually stalled or left me stranded, so I just lived with it. Just a couple weeks ago, it suddenly became worse, with the car actually stalling on occasion, but easy to restart and go. Finally it started doing it all the time, losing power before the stall with restarts very difficult with lots of backfiring. I have some mechanical ability, so did some of my own troubleshooting. Checked the Weber 40DCOEs to my ability limit-that is, pulled/examined all the jets and floats, all good there. Fuel pump/filter OK. In the distributor, did note the rotor was quite rough, tho the points/gap were OK. So put new rotor in with new distributor cap and changed the points/condenser for good measure. I put new spark plugs in 2 years ago, pulled them and checked them, seemed OK and equal/normal in carbon buildup. Did have one bad spark plug wire via multimeter testing, so bought a new set and replaced all the wires. The result of all this did help quite a bit-car starts normally, still same issue with rough cold idle but no losing power/stalling under throttle and revs to 5000+rpm with no issues. The only remaining problem is the car will not hold idle, even when fully warmed up now. Coming off throttle to idle, its all good at about 1000rpm, but only for about 3-5 seconds, then the engine stalls. Restarts easily.
Just wondering if anyone out there has any ideas/suggestions about anything else I should check. I'm beginning to think it may be a deeper/more complex issue with the Webers, which would be outside of my Alfa mechanic skill set. Wanted to get any advice/opinions from the Board first(as many members here have expert-level Alfa knowledge and mechanical ability)before I surrender and take the car to my Alfa mechanic(he is great and sure he could diagnose/fix the issue quickly, but I still like to do my own work as much as possible)
Just wondering if anyone out there has any ideas/suggestions about anything else I should check. I'm beginning to think it may be a deeper/more complex issue with the Webers, which would be outside of my Alfa mechanic skill set. Wanted to get any advice/opinions from the Board first(as many members here have expert-level Alfa knowledge and mechanical ability)before I surrender and take the car to my Alfa mechanic(he is great and sure he could diagnose/fix the issue quickly, but I still like to do my own work as much as possible)