My buddy has an 88 Montero that he put the same carb on, He has lots of trouble tuning it too. Like you said, all the emissions has to come out and from there it's a lot of trial and error until you figure it out. Also, from what I've noticed on my 87 and my buddy's 88, the Monteros like to have a good amount of backpressure in the exhaust to really run right, so you might look into that. And even after we got the Weber dialed in, it still doesn't like to be off camber for very long at all. My carb is still stock and I have a much easier time when we are off camber. That's the most I can say to help ya there... hope that helps.