i have this thing pretty close to running well but there is still a slight surge at idle in open loop. it seems to be completely independent of the iac and spark advance. i disabled stall saver, which helped, and flattened out the idle ranges of the SA table. the iac is not causing it because it is only varying 1 or 2 steps here and there while this is happening and the SA is staying pretty much stable too, yet the rpms incease and decrease in a classic surge pattern. the only thing i can see thats off is that when this is happening i am running a bit rich, but i thought the afr needed to be rich on cold startup. surging stops when engine temp warms up a bit and afr approaches stoich. any suggestion?

 

There's filtering involved in figuring the MAP readings. Depending on how much variance there is, it will cause the engine to seem to preiodically *load up*, and then clean out, giving a *surge* to the idle. Big cams at idle generate their own self ERG'ing effect, and it's impossible to eliminate it.

Generally adding timing, and running a lil rich helps. I'd be careful thou not to get too carried away with adding timing thou.