Runs rough for 20-30 minutes then smooths out

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I dont believe there is an ECU in a 328... its a Kjet set up with Lambda... so just an O2 sensor that richens or leans out the mix... the Marelli units are ignition curves... likely not an issue. The thing that makes me think vacuum is the 20- 30 min of running time... something is changing as it warms up... so its got to be flexible and heat dependent... it could be wiring, or hoses, or rubber o rings.... from my personal experience it was usually vacuum hoses... mine were mostly original, and I replaced them all over time... it then ran steady like a rock. my only other starting issue was cracked connectors under the pass. foot well, and behind the fuse block, but in those cases you could hear the pump running or not.

 

Can you fix a temporary telltale light on the pump terminal to confirm/eliminate the power interruption. Perhaps also another new relay- they’ve been known to fail out of the box- or swap with a similar known working one?

 

Higher current rating and the date maybe? Hopefully your professional will listen to the tests you have done and not just throw parts at it.

 

The difference is the mfg date not a difference in spec. Similar to date codes on tires.

15W 2022 = 15th week of 2022
48W 2019 = 48th week of 2019

 

Glad it’s fixed. Frustrating though!

 

The reproduction dist caps can have the wire insert areas not be deep enough, and the little screw that pins the wire might have been poorly connected. But I would not have thought that would present only on start up. I suppose the heat might expand eg. the coil wire connection enough to make for a better connection. But congratulations for getting this sorted!