I've had this happen after setting the throttles. Go back and recheck all your adjustments. I'm betting something got fudged. Been there, done that.

If not that then you have extra air coming in from somewhere....a hose knocked loose or such?

Cheers
DD

Submitted by dougdwyer1@com… on Mon, 06/25/2012 - 23:43

"If it ain't broken I'm gonna keep fixing it until it is!" Tee hee hee :-)

Glad it's sorted. I'm betting that many V12 DIYers have been through this. It certainly can't be just you and me !

Cheers
DD

Submitted by SE21-33540J on Mon, 06/25/2012 - 17:36

Doug,

Thank you. I started over again this time not in a rush. I also released the throttle rods before setting the throttle butterfly on each side. I finished off by adjusting throttle rod length so each side allowed the carousel to move from full stop to full throttle at the same time that the butterfly also was at full stop (.002in) or full throttle. The results are a smooth idle at 750 RPM and smooth acceleration, it has never run better. Now I am going to leave it alone and try not to "fix it" again.

Submitted by SE21-33540J on Thu, 06/21/2012 - 19:37

Okay. What did I do? I decided to make some small adjustments in my throttle settings. Followed the shop manual for a 6.0 V12, set the butterfly to .002 inches/.033MM, adjusted the stop screws, adjusted the linkage and now my car starts fine but at idle it surges repetitively from 1000 RPMs to 1500 and back down and back up and back down etc.

This is a perfect case of if it isn't broke don't fix it. But I had noticed a recent drop in mpg and thought maybe my settings were off. Any help is appreciated.