good post, I have had simmilar problems but with a 22r. I like engnbld's idea of checking for leaks on the intake with a little ether <img src="/forums/images/graemlins/kewl.gif" alt="" />
i am not sure what my low/rough idle is all about, its so variable that i can't pin point it to anything for sure.

AFM replaced with good unit. MPG has suffered a pinch-the old AFM was leaned out a bit in an effort to compensate for other problems. The idle issue seems to be a bit better, but it's not solved completely.

When cold=no issue. When starting up when the truck has sat for a short period of time (under an hour or two), it will idle really low, but settle right back in to normal after I drive it just a bit.

I'd probably leave it alone but it's just one of those things that is frustrating me to no end. I like my vehicles to be 'just right'. Plus, I'm nervous about the smog nazi. I have a test in a few months. I think I'll get a pre test this week and see if I'm OK. I haven't had one done since the rebuild and I'm curious as to what the sniffer says about the new Street RV head and 261 cam from EB.

I had a similar problem with my old truck, which I never really found a conclusive answer to. My 4runner however started running really rough at idle a couple of weeks ago, seemingly misfiring at idle badly. Once it revved passed about 1500 though it would smooth out, or at least I couldn't tell. I ended up putting some Heet in and my problem went away. My best guess is a combination of bad gas with letting it sit for a while with a low tank let moisture build up in the tank. I would kind of doubt that was your problem, but it is a cheap easy thing to try to rule out any gas quality/moisture issues.

I just found a loose connection between the header and the down pipe. Since snugging that back up, I've noticed that the idle problem has been showing up MUCH less frequently. I suspect the smog test would have been a bit better, too.

However... I've still got that funky after market cat on there. It's going to be replaced with a new one. I was going to eat it and just buy an OEM cat, but I've been informed of a new law in CA that appears to have required aftermarket cats to be much more efficient. I'm going to have to check one out and see how it compares to OEM. But that's a smog issue, not an idle issue.

If I ever figure out the idle stuff, I'll be sure to post. For now, I'm at a loss.