Ok, ive been having a rough idle on my 99 4.0. After research i thought i had narrowed it down to intake gaskets. After changing them my lean codes went away but i still have a rough idle. While in the back yard the other day i decided to try and lock in in 4x4. The transfer case engaged but it was still in two wheel peel. So this tells me the hubs are not engaging and i have a vaccum problem. I have not been able to find a leak anywhere, any ideas? Could it be the smog pump?

 

sry to say but the ohv doesnt idle like a sohc. it will b rougher. do a compression test n c if all the cylinders are realitivly even

 

ive got a 94 4x4 thats started dying on me at stoplights and such it starts right back up but the rpm bounces and once it gets under 1000 it drops strait to 0 and is dead again its got to the point now i drop it into neutral when i know im going to be waiting to i can give it gas without rear ending anybody any ideas on what to look for