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I haven't yet bypassed the ballast resistor but that's next I guess. I do have a multimeter, but I don't think I will be able to test the connection right at the gas tank because the tank we put on has it's opening and connections on the top rather than the side. Not accessible unless I drop the tank. Once the weather warms up I may do this anyway because there is a leak somewhere at the top too. Are you suspicious that the fuel pump is failing?

I'm wondering if there is anything I can check while it's not acting up? Will checking the fuel pressure while it's running ok tell me anything ? Here's why I ask: My local auto parts place can order a gas pressure tester but meanwhile, I decided to go over all the connections again. The one in the taillight was quite rusty, so I just cut it off and regrounded it nicely. I was pretty excited because at first, I couldn't get it to act up and thinking I would report back that I had resolved it, but then last night we had an actual snowfall so I was able to test it for real. It did go for much longer before it had the problem, but then just as I was finishing up .... I heard the dreaded "put-put-put" sound which I know means it will start missing and lose power soon. Sure enough it did, but not as badly as before. And I don't know whether it means anything, but when it idles after that, it is actually very low... 300-400 rpm. Its usual idle speed is about 1200 rpm. Even after I get a fuel pressure tester it may not snow any more this year, so that's why I'm asking if there is anything else I can check. Thanks again

I will for sure check the possible fuel issue first. Even if I end up buying a gauge, it's cheaper than a computer! I am just trying to understand in my mind why it might be happening. Thanks again for your advice folks.

No such thing as Autozone around here, but I will see what I can figure out. Maybe just buy one for fun.. I don't understand though how a fuel starvation issue could be quickly but temporarily resolved by simply restarting the engine. That's why I was thinking it was the computer… restarting always helps them!

Thanks so much for your help. I had no idea I would get such detailed responses. Yes, the first thing I did was put in some "dry gas." And fresh gas. It's true that the truck isn't used frequently, but I always add a good fuel stabilizer and try not to overfill it so the gas is fairly fresh anyway. And it's still snowy here so I am using it once a week at least, and more now that I'm trying to sort this out. I'm all for finding some other cause that doesn't mean buying a new ECU. I'll try to find a pressure gauge to borrow or maybe buy one if it's not too much $. Umm…. Sorry if this is a really dumb question but… I have a gauge that was on an air compressor … would that work?

Ok, I will find a way to test the fuel pressure. It sounds more important than I thought. So, low fuel pressure might cause the ECU to send a false message about the mixture and maybe bypassing the resistor gives more pressure which would help? Am I understanding the theory? Any thoughts on why turning it off and on again immediately would make it work ok for another 5 or 10 minutes. Could turning it off reset the ECU and then it would work for a while again?

Thanks for the response. Maybe I should have mentioned too that the fuel tank has been changed. It's from some other vehicle (not jeep), but the pump and sending unit are still the original… just sort of bent to fit. Not sure if it's relevant. And the fuel gauge doesn't work of course. Yes, while it's happening does feel like gas starvation as you said, but even when it is sitting still not under any load, I can't rev the gas... until I restart, and then it's good. I will double check that ground, but I would imagine that a bad ground would be more inconsistent, no? I can try to get a gauge, but one of the mechanics said " if you get gas squirting out of that port, you should be ok. The exact pressure doesn't matter for now" Any thoughts on that? Right now I'm not worried about fine tuning it and mileage isn't an issue; I just need the full power back for plowing. Sorry to be such a newbie but could you explain how to bypass that resistor? Just join the two wires? Is it a way of testing or maybe a "fix"?

Hi folks, I've been browsing this forum since I got my 89 Comanche a few years ago and have picked up many great tips. Now, I am stuck and request some help. I have an 89 Comanche with the 4.0L 5speed. It's a rust bucket and will never go on the road again, but has been good work truck plowing my laneway and hauling my firewood. The problem now is that after a few minutes (maybe 5 or 10) of plowing snow, it drastically loses power, and won't respond to the gas pedal. It farts and pops and will barely go at all. It will sit and idle fine, but not rev up. The odd part is that if I turn it off and then right back on again it will work fine for another 5 or 10 minutes, then the same thing happens. I'm not talking about letting it cool down … just off, then immediately on again and it's ok. Since I can't take it anywhere, I have asked every mechanic I have ever paid to work on my vehicles for advice. Their consensus is that it is some sort of computer issue since it isn't a consistent problem and seems to reset itself on restart. I am a handy enough guy but not a mechanic, however I am still willing to try whatever I can do on my own to get it going properly. I don't have any electrical testing tools and even so, I am not sure I could use them properly. So my question is….. should I look at changing ECU? Most people say it hardly ever goes bad but what else could it be? I haven't been able to find a used one so I am looking at buying a new (reman) one. Here's what I have done so far. I had another coil+ignition control module from a wrecker and tried that (after cleaning all it's connections) new fuel filter tighten most intake manifold bolts (some I couldn't reach) cleaned throttle body cleaned IAC reset comp disconnected and cleaned every connector under the hood I could see refreshed as many ground wires as I could checked vacuum lines (I think all of them) Thanks so much.. PS... I haven't yet cleaned the connectors at the ECU because so far I haven't been able to get it off due to it's awkward spot and my old and inflexible body :-(