Lean mixture on drivers side of engine after alternator change, 2.7l /6 Options

[tornik550]

I have a /6 2.7l with dual Weber ida3c’s. The engine was running great then last week I did two changes on my car. One was that I repositioned my air fuel gauges. I have dual AEM widebands- one for the drivers side bank and one for passenger side. In addition, I had to do some minor wiring work on my alternator which required me to remove my carbs, linkage, shroud, and fan. I did not remove the fuel hoses, I just unbolted the carbs and moved the out of the way. There were no major changes. I put new carb manifold gaskets on when reinstalling. No carb adjustments were made.

Now when driving, the 4,5,6 bank now reading a air fuel ratio of >21 and the other bank reads normal. The car is now sluggish from idle and idles rough. Occasionally when Erving the engine, the a/f ration shots down to 10 for a second. Seems to be running hot and doesn’t start as quickly as normal.

Things that I considered that might have caused the problem.
-plugged idle jets- checked and cleaned- no change
-since I just moved the gauges- some sort of gauge issue. I doubled checked all wiring and all seems fine. Also- why would the engine be sluggish and hard to start if it was just a gauge issue? Doesn’t seem to be the case.
-I check the linkage and there were no changes and everything seems to be functioning the smoothly. No adjustments were made. Could a linkage issue cause a lean issue like this?
-maybe I bumped the distributor when removing the shroud? Why would only one bank be an issue then?
-fuel pressure issue? I have a gauge before the fuel line splits to each carb and it’s running at 3 psi.
-intake leak? I replaced and double checked each intake gasket.

Ideas?

[mskala]

Not an expert, but I would check floats and fuel levels on the bad side. Maybe hung up since moving carb around.

[Dave_Darling]

If you took the carbs off and then put them back again, you may have introduced a vacuum leak. Double- and triple-check all the joints in the intake.

--DD

[rgalla9146]

Any chance one of the carb down link adjusters is attached but loose ?.....
loose jamb nuts ?

[tornik550]

I’ll check the floats and see if there is movement.

What is a good way to check for a vacuum leak? I don’t see or hear anything unusual.

A loose link is possible however if it was the issue- would it cause a lean issues like this? I had previously visually inspected the links however I did not check to make sure all the nuts were tight. I wonder if I could have bent a linkage piece? At would point I had a hard tine getting the shroud off.