jerseYJoe Posted October 29, 2016 Share Posted October 29, 2016 So I have an 86 2.5 5 speed custom, which recently started bucking and stuttering at random intervals for a random amount of time. The first time it happened I checked under the hood and noticed and replaced a cracked vacuum hose going to the map sensor., which didn't fix the problem. It seems like a fuel issue since twice it actually stalled on me, however the fuel pump and filter were just replaced about 5 months ago with a bosch pump. Just wondering if there is anything specific I should look for before I tear into the fuel tank again. Thanks for any help. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 30, 2016 Share Posted October 30, 2016 at the vacuum hoses below the throttle body, and make sure your intake/exhaust manifold bolts aren't loose. Link to comment Share on other sites More sharing options...
MJCARENA Posted October 30, 2016 Share Posted October 30, 2016 Does the 2.5 have a crank position sensor? My 89 4.0 XJ would act up like that, and found that if I unplugged and reconnected the sensor connector it would run good for a couple of months then start doing it again. Disconnect and reconnect and it was good again. Finally cut out the connector and hardwired it, no issues ever again. Don't know if this is your problem ,but worth a try. Link to comment Share on other sites More sharing options...
MeanLemons Posted October 30, 2016 Share Posted October 30, 2016 Had same thing happening to me with my 99 5 speed. It was the oxygen sensor. Link to comment Share on other sites More sharing options...
jerseYJoe Posted October 30, 2016 Author Share Posted October 30, 2016 Great thanks, will check all of that asap. Link to comment Share on other sites More sharing options...
SVPete Posted October 30, 2016 Share Posted October 30, 2016 Might want to read/search some of the threads......including 4.0forlife's Random Power Loss here on the first page. Link to comment Share on other sites More sharing options...
jerseYJoe Posted November 2, 2016 Author Share Posted November 2, 2016 Ok still haven't had time to dig into this, but I figured I might as well replace the vacuum harness while I'm in there. All the parts stores say they either don't have one or it doesn't fit my 86. Is this true? If it is, does anyone have the correct part number or some other resolution for it? Link to comment Share on other sites More sharing options...
cruiser54 Posted November 2, 2016 Share Posted November 2, 2016 Ok still haven't had time to dig into this, but I figured I might as well replace the vacuum harness while I'm in there. All the parts stores say they either don't have one or it doesn't fit my 86. Is this true? If it is, does anyone have the correct part number or some other resolution for it? Look near the throttle body....... Link to comment Share on other sites More sharing options...
jerseYJoe Posted November 3, 2016 Author Share Posted November 3, 2016 I just went out and took a quick look while the trick was running. I jiggled all lines at and near the throttle body, including the throttle body itself to see if anything was loose or if I could replicate the issue. Bolts seem tight, nothing really seems abnormal at a glance, and of course the truck didn't miss a beat the whole time. Seems to happen more while under power. Will check more thoroughly friday when I'm off. Link to comment Share on other sites More sharing options...
cruiser54 Posted November 3, 2016 Share Posted November 3, 2016 With the engine idling, spray some carb cleaner around the throttle body, where the intake manifold meets the head, and those vacuum lines under the throttle body. If there's a vacuum leak, the idle will change. Link to comment Share on other sites More sharing options...
jerseYJoe Posted November 4, 2016 Author Share Posted November 4, 2016 I sprayed carb cleaner all around the throttle body and all other vacuum lines and what not and had a slight change in idle when it hit the short hose coming from the top of the intake manifold that 90s off toward the firewall into a hard line behind the TB. I replaced that hose, do you think that could have caused my issues? Link to comment Share on other sites More sharing options...
cruiser54 Posted November 5, 2016 Share Posted November 5, 2016 Possibly. Did you spray the other areas I suggested? Checked the intake manifold bolts to make sure they're not loose? CLEAN your grounds per Tip 1 on my website. Link to comment Share on other sites More sharing options...
jerseYJoe Posted November 5, 2016 Author Share Posted November 5, 2016 I will recheck grounds, I added ground to the block and chassis in the past already. I also found a leak at the intake where it meets the head, so I got a new gasket and will be replacing that soon. Bolts weren't loose, so I figure I'll just take it apart and and change the gasket while I'm in there. Am I correct that the torque specs are 23# on the 2.5? Thanks for all your help. Link to comment Share on other sites More sharing options...
jerseYJoe Posted December 10, 2016 Author Share Posted December 10, 2016 Just wanted to update this thread in case someone else has the same issue. I replaced the map sensor and intake manifold gasket and the problem has disappeared. Sadly though I just sold the truck to a friend of mine and bought a 2001 xj because I need a reliable dd. My 2 yjs are enough projects for me at the moment, but I will be back! Thanks for the help Link to comment Share on other sites More sharing options...
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