1971 1750 Spider “hunting” at idle
Been away for some time, but now back into the thick of it. A few months back my Mom passed away and she left to me her 1971 1750 Spider. I am not unfamiliar with this vehicle hence my sign on name... she had this car since new and Ive known it my whole life. It was also the first Alfa I ever drove or worked on when I was a teenager; it also started me with the sickness which ultimately led to my Quadrifoglio, GTV6 (long ago sold) and 164S (which just went to Alfa heaven).
In any case, I moved away from my home state of PA, and when I did, the car sat for some 11 years in a dry garage... but wasnt touched.
After receiving ownership of the car, I drained the fuel tank, replaced the rubber fuel lines, had a mechanic service the SPICA pump (de-gunk it and change out the oil filter), changed air filters, new brake master, new clutch master/slave, new rubber on all four corners, oil change and lube, new fuel filters and rear section fuel pump, rebuilt starter etc....
Car starts and “runs”. Can drive the stink out of it.... but at idle it comes close to stalling with every full cycle of revolution. Its not misfiring, its not blowing smoke, it accelerates just fine.... but at a stop, it surges from 200 rpm -800 rpm and running cold or hot doesnt seem to matter.
Fuel pressure seems good, adjusting the idle air screw doesnt seem to help. Thermo switch on pump is set for normal weather...Not sure what else to try
Any suggestions are welcome.