Hello all. I have a problem that in 4th and 5th the jeep sputters, shudders, pops, and I can't maintain speed at all. I asked around and got an answer of a clogged CAT. I just put on the new exhaust and same issue. I am really frustrated with this. I am no mechanic but any suggestions would help. I have an 89 4.2L 5 speed with MC2100 carb. I am also having idle issues where it is always above 1000. Any thoughts? Thanks.
I have had the same issue and have been battling it for the past 4 months.
1st must have a 1.08 carb.
front port vacuum port for the timing if ya don't have one drill one use a dremel with a small tip tool to cut into the venturie area and make the drilled hole 2/3 in for a 1/4 inch tube and jb weld it in tadah vacuum port.
tfi is a must timing is right at the verge of upper gear spark knock at in 4th or 5th cruising, you will need to change the timing springs out as per the TFI upgrade. mr gasket timing advance spring kit for all fords
you will need #47 jets.
you may need to change the power enrichment valve to a lower hg rated one.
the accellerator vavle should be ok. regardless you may need to adjust for stroke though.
I used a carb from a 76 for f150 with ford 302 drilled my own vaccuum port and it seems to work great and way better than it did with the over sized 1.21
spark plug gap seems best at 40.
good luck and use the search there is lots of info here.
Silver Rubi JK unlimited.
89 YJ, 4.2, 5 speed, 2" lift, 235 75 r 15 M/T. CRT's HEI, MC2150 1.08, OBA, 120V inverter. removable Light bar, 10 hella lamps, trail rack w/ jerry cans, champion winch, high lift jack, C.B., lined tub. H4 Conversion headlamps, reveiw mirror w map lights. royal blue with matching trailer.
I have the 1.08 carb. You lost me on the rest. I have several ports on the carb. I have all of the correct lines running as far as I can tell. I have seen many posts and followed the descriptions and diagrams. As far as the tfi, power enrichment, and other things I am clueless. I was going to change the dist cap and put in the Bosch Platinum plugs I have had sitting here for months. I still don't know why it is only in 4th and 5th gear though? Sorry but I am an idiot and far from a mechanic but trying...
If you still have the stock ignition that could be the problem. When I did a TFI my 88 ran a little better but still had crazy idle issues. Once I ditched the TFI and went to a HEI I have been as happy as a clam. All my idle issues went away. Not so much as a sputter.
Its not a jeep if it dont have 4wd.
as he stated his problem is sputter in 4th or 5th probably and the jeep probably looses power and it seems like your foot is to the floor.
I have already spoke in regard to all this and i'm not retyping do a search showing mc 2100 or 2150 with wraithyjeep you will find all ya need to know.
the power enrichment vavle again search for that and you will find links to an mc 2100/50 site that tells ya what ya need to know..
I still loose about 300 rpm one i hit cruising speed and i have to step into it a bit more but atleast now i can get it up to 140 km/hr
also be sure to use ported.
and the springs for the dissy, are from mister gasket company 925d is the kit number probably 4$ or so down there.
just do a search and you will find it all. start here