im having the same issue after an efi swap on an 84 pickup going to 87 efi. im missing the egr modulator as one of the ports broke off, i have all my vacuum crap plugged but ive had this issue on a late model 22re (89-up) and the egr was vacuum routing was the culprit.

was wondering if you ever found out the problem with your truck.
i have simular issue after rebuild, i have no egr, crane cam, lce full length tube header. i also turned up afm 3 teeth before i even started driving it around.
i have a wide band o2 i was watching fuel mixture with when i first got it going, the cam i choose is on the edge of radical, anyway my reading are 14.3-14.7 up to around 3000 then it will start going a little leaner up to 15.-15.3 till 3500 then the fuel comes in but just a little richin it up to about 14 and then starts to go up with rpms to the 14.7 or about in there, the mid 14's.
while cruising though i didn't notice any changes in a/f mixture when i felt the studder, it in the 2400-2900 range under normal driving, not lead footing it, i have only had it going for a couple of weeks now, so i am interested to know what you have found out about yours.
i had the lce camshaft in the motor the efi split duration pro, was not happy with the performance of at all, i'm not drag racing or rock crawling but i would like the power where i need it and theres wasn't up to par was actually disappointed i think its a stock cam or feels like it.
the crane cam i choose was 704-0014 this was a step up from previous motor i sold out of my truck and wanted to try lce that everyone talked about, and this is where i am at now, lce up for sale , crane installed.
hope to here from you.

surely one of us has found this problem and knows the fix.

thanks for lots of input. <img src="/forums/images/graemlins/kewl.gif" alt="" />

Still no luck for me. Might have to attempt fuel pressure check? What about removing the vacuum line going to the fuel pressure regulator? Would that do anything?

Try bypassing the VSV that feeds the fuel pressure regulator:
http://www.4crawler.com/4x4/CheapTricks/22RE_Engine_Pix/8.html

i havent any vacuum lines to speak of, the only 2 i have are going to power steering, everything else is pluged up except for regulator. i not really having the idle problem seems to be higher in rpms and is so inconsistant it is being a real problem to find.
i will try and get some pictures of my engine bay.

OK, we might be getting somewhere here. Tuesday, I was able to spend some time troubleshooting and noticed a marked decrease in the misfire when I pull/plug the vacuum line off of the fuel pressure regulator. Now, when I plug it back in, the idle speed drops a bit (as the manual says it should). But, is it a problem if I leave the vacuum line off/plugged and run the truck for a period of time? Don't know if the increase in fuel pressure is going to harm anything. <img src="/forums/images/graemlins/confused.gif" alt="" />

Engine will run too rich at low load and idle. May not hurt anything for the short term, but gas mileage will drop and it'll be sluggish off the line. Cat may wear out faster as well.

Try connecing vacuum straight to the FPR, bypassing the vacuum valve.

good idea. I'll give that a shot and report back later.

<img src="/forums/images/graemlins/confused.gif" alt="" /> Crap....bypassing the VSV and going straight to the FPR did nothing to reduce the misfire/studder. Now, leaving the vacuum line off of the FPR and plugging it DID make it smooth out. Is this a sign of a fuel pump starting to go bad??? It's only 21 years old <img src="/forums/images/graemlins/smile.gif" alt="" />