Make darn sure the accelerator pump is shooting as soon as throttle is pulled. Any delay there will cause a lean spike.
This is another reason I'm a BIG fan of A/F meters so you can see what's happening in actual driving situations. Saves time in the end. No guessing and throwing parts at it. Make it portable and all you need is a bung in the exhaust headpipe/collector. You can do a lot with an A/F meter and vacuum gauge.