sick jeep

this morning
i got in and it started right up (as usual)
ran like a dream but after about 6 miles it started missing.
that got worse and worse until it was running on maybe two cylinders?
until it was undriveable and i got stuck on the hiway with a dead jeep.
i waited maybe 10 minutes and it ran ok again.

new gas/plugs/wires/fuel filter/pertronix
all of those things work.
patrick suggested awhile back that humidity was the cause.
but does that explain the running great/crappy/great?

 

I had this problem in an old Mustang once. It ended up being water in the gas tank.
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I'm in with the coil, My 86 jaguar had the same issue and cost me a lot of time and money for such a simple fix. When it got "warm" it quit, cooled off and worked fine for a few. I'd try that IMHO.

 

It wasn't humidity. It was about a gallon or two. It would rain and the gas cap didn't seal too well so the tank started to fill with water (either that or someone deliberately filled my gas tank with water). The gas pick up was just above the water line so the engine would run great until something would cause the water to "slosh" up into the fuel line. Then it would run rough and die. Sometimes it would get a slug of water and just die suddenly. I ended up draining the tank and putting a new gas cap (tighter sealing and lockable) on the tank. Never had water trouble again.

I agree with changing the coil though. Heat can cause a temperamental coil to display the issues he is having. It works great when it is cool but as it heats up it starts to fail. Once it cools down it starts working again.

 

gas cap venting properly?? next time it does it remove the gas cap and listen to see if it is under vacuum.

 

Symptoms defiantly point to this as a possible cause.

As is the coil.

The waiting 10 min, and running fine a key bit of info here

 

new gas
new dist cap
new plugs
new wires
new fuel filter
new pertronix
new coil

tried gas cap trick
i put heet in it.

no difference.
my lets throw money down the toilet fund is all gone.
i have had it with this P.O.S.
i dont trust it to go around the block and i cant count on it.
i am ready to part it out and crush whats left.

too bad i cant return all those parts i wasted money on.

 

Did it backfire any thru the exhaust? The last ignition box I had go bad would stumble, then BOOM! Hard on mufflers. Also have you ruled out carb icing?

 

Can you tell the condition of the inside of the gas tank? I had one that a PO had put some kind of liner sh*t in. It peeled off and would plug the fuel pick up. Let it sit and the pieces of the liner material would get away from the pick up and it would run fine. I ended up replacing the tank because I couldn't remove the liner material. Just a thought.......

 

no backfires.

carb icing?

 

i removed ,cleaned and patched this tank myself when i bought this albatross.

i dont have one more dime to waste on this.

 

Might want to pull the fuel line loose and just run a tank out of a lawnmower to isolate the problem. Check your oil level to make sure there is not a small hole in the fuel pump diaphram that can't suck when it is warmed up. When it stops running, do you still get a spark at the plugs? Fuel or fire, got to be one or the other.

 

i havent checked spark when it dies because the only time it does it is during blizzards at 5 am on the side of a busy hiway.

this morning i was hoping not to get nailed by a snowplow.

 

A trick I use is to get an old style timing light that plugs in series with a spark plug wire. Arrange it to where you can see it flash while driving and you will quickly know if it is still getting a spark.
As far as the carb icing, sometimes if the humidity and temperature are just right, the inside of the carb will frost up from the fuel vaporization and restrict the air/fuel flow. Once it has set and the engine heats the intake, it will run again. Don't know if it is your problem, just grasping at straws. Had a friend with side draft Webers on an SR5 that would freeze up often. Not likely on a stock setup, but possible. Has it ever run well? Glad you did not make the morning newscast.