702_MJ Posted August 7, 2012 Share Posted August 7, 2012 Ok I have an 86' with a 4.0L. About a month ago it left me stranded in town. Ran fine there, went into the bank, came back out and fired her up and she had really rough idle, wouldnt rev and would slowly die. Eventually after a while she just cranked and I couldnt hear the fuel pump.Had no pressure at the rail, so I replaced the pump....she ran fine after. Now just the other day she did it again, but ended up acting normal after like 30 seconds, was thinking maybe water in the fuel because I noticed I had a hole in the tank about an hour prior, and I live in the wettest part of Hawaii so I wouldnt put it passed water getting in. So I dropped the tank today, couldnt see any water. But I do need a new tank.... Any thoughts on what could cause this little random stumbling idle? What else to check? Link to comment Share on other sites More sharing options...
HOrnbrod Posted August 8, 2012 Share Posted August 8, 2012 Change the fuel filter if you haven't already. Link to comment Share on other sites More sharing options...
702_MJ Posted August 8, 2012 Author Share Posted August 8, 2012 Changed it with the pump.....I'm gonna change it again just cuz maybe what's left is sitting in it. I'm thinking of buying a new tank and running a fuel system cleaner through it after and see where I am when the dust clears... Link to comment Share on other sites More sharing options...
702_MJ Posted August 10, 2012 Author Share Posted August 10, 2012 Fixed the tank, changed the filter, added lucas fuel treatment......and now it kinda is hard starting. Itll crank longer than usual and kinda stumble to life then run like she use to. Gonna bypass that resistor on the fender, no idea if that'll help at all. Gotta wait till next week to throw a fuel pres gauge on it. Any other suggestions? Link to comment Share on other sites More sharing options...
ComancheKid45 Posted August 10, 2012 Share Posted August 10, 2012 When you changed fuel pumps you did remember to tighten the hose clamps on the fuel hose connecting the pump to the sending unit right? I forgot to do that once and experienced a very similar issue. ;) Link to comment Share on other sites More sharing options...
702_MJ Posted August 10, 2012 Author Share Posted August 10, 2012 Yep I remember doing that cuz I changed it as the original was starting to rot. Link to comment Share on other sites More sharing options...
wj87mj Posted August 13, 2012 Share Posted August 13, 2012 Check your fuel injectors for leaks. It may be hard to tell if the leaks are not bad yet. It sounds like the same problem I had with my 4.0 in a xj and my mj. You can get a seal kit which is pretty inexpensive. Replacing the injectors will cost a lot more. speaking from experience, if you decide to replace the injectors it is probably better to do them all than just the bad ones, so you do not have do do it all over again when the others go bad. Good luck, and thanks for the question. I have been reading this site for a while and your question pushed me to join. I hope the information helps. Link to comment Share on other sites More sharing options...
702_MJ Posted August 13, 2012 Author Share Posted August 13, 2012 Oh yeah thats a good one. Ill have to double check them, I know they are the injectors that came with the 97' 4.0L. I think I put a new o-ring kit on when I swapped it in, since I swapped in my intake and injector rail. Great suggestion Ill go look, thanks Link to comment Share on other sites More sharing options...
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