OK,
I’m beyond frigg’n baffled on this one. :-|

1987 YJ, 258 bored +30, balanced, Webber 38 on spacer plate, 4700 miles on the engine, transmission and T-case (w/the 231 SYE). It has the Nutter bypass and TFI with new coil and wires (there is no computer module or smog), stock intake/exhaust manifolds. All the plugs are a beautiful tan and gapped at .45 for the TFI.

We’ve put over 4000 miles on this motor with no problems, then my daughter started having problems a couple weeks ago while ‘just driving’ (she’s not a speed demon either) and said it “just quits” on her at various speeds. I put almost 400 miles on it to/from work with out a problem – until today. At 30mph, it just stopped running. At 45, it just quit and at 65 on the freeway, well . . . I coasted to the side of the road. All within 45 minutes!!! Each time it takes 1-2 minutes before it’ll crank over again. Turned around and came home. Each time the oil pressure was 30-50 PSI.

I’ve checked:

All electrical connections and plug wires
All fuel system hoses (new on rebuild)
fuel pressure regulator is set at 5PSI for the Webber.
Vacuum lines (new on the rebuild) are in place
Starting it up a little while ago it back fired through the carb while cranking (not sure the state of the power valve/accelerator pump now). this indicates timing, but...
Timing is spot on – though the timing light does ‘shift’ 5-6* like the spark is early/late occasionally (random intervals 5-10 seconds apart) and I wrote that off to interference with #2 wire, but . . . I'm puzzled 111!!!

This happens anywhere from 30-70 degrees ambient temp. Engine is never over the T-stat at 190-195*, it’s still winter here :roll:
Vapor lock is what I’m thinking, though I can’t see how since the fuel pump, lines and filter are cool to the touch after running it around for 20-30 minutes or so – well within the time that it quits. 111!!!

I’m about to go reroute the fuel line from its stock position well away from the valve cover and heater hoses just in case. And I’m thinking about popping the valve cover off and checking torque on the lifters (hydraulic) just in case, but there is no valve chatter that I can hear with the stethoscope.

I’m open to suggestions and any straws I can grab at. Erin needs this for college, and the other 2 running trucks are needed for my wife and I to get to work, The man-child is SOL until we can get his Blazer rebuilt – or I get the Waggy running. :oops:

Went looking for a replacement carb for the Webber - an MC2100 and NOBODY in the 6 parts stores near me can get one this week (and the cheapest is $235!!)!!! :shock: NAPA doesn't even lit it 111!!!