Usually, warm-up regulators have the opposite problem, they don't supply enough fuel when the engine is cold, or help enough with enrichment when you try to accelerate.

I would check the oxygen sensor. If it is worn out and giving a low reading, the lambda system will try to enrich the mixture. A quick test is to disconnect it and see if the mixture situation improves.

You might also check the fuel distributor piston for movement. Jumper 30 to 87 at the fuel pump relay so the pump runs. Press the air sensor plate down and be sure that it moves easily, and that it returns to rest smoothly.

If you have an old-fashioned dwell meter or even a multimeter, you can check the on/off ratio, which will tell you what the system is doing to try to control the mixture. Lots of posts on this.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe