Originally Posted by wdc
I have a jeep wrangler 1990 inline 6. I have lost vacuum pressure to almost everyting. Four wheel will not engage. Engine dies at a stop when engaging the clutch. When at idle after warm up rpm's go up and down. Will not idle smoothe unless I throttle slightly. I do have vacuum on vacuum fitting. I have also noticed a slight back pressure sound in exhaust when going down hill. I have checked all the hoses (very many of them) and can't find any leaking. If anyone has any suggestions or solutions to this you help is greatly appreciated. Thank you!!!!!!!
it's possible you have two unrelated problems. the fact that your 4-wheel drive will not engage is not that uncommon in these jeeps. search the forum for posi-lok solutions and that might help.
as for your idling issues, yes it may very well be a vacuum leak, but assuming you have that old carter carb, you may just have clogged idle tubes. there are a number of threads on this issue, but if you want to tackle your carb, without tossing it and swapping in a weber or mc2100, then try these fixes.
consider this carb fix:
with these pictures:
and consider drilling out the venturi idle tubes to 0.040" with a #60 drill bit (by hand).
Also, a TFI ignition upgrade is great for that engine. search the forum for TFI upgrade info, or got to this site:
also, this site is awesome. http://home.sprynet.com/~dale02/list.htm