Thanks for the links. I think he definitely knocked them out of place.

 

Another possibility is an electronic leak detector, basic ones have come down in price. Here's one for under $50:

https://www.amazon.com/s/ref=sr_gnr_...qid=1471396098

 

I have a rough idle while in gear its kind of intermittent but happens id say 90% of the time
Im sitting at a stop light/sign. Put it in park or neutral, it goes away! I have tried numerous things... Jeep runs good when you are accelertating or in neutral/park feels like it has a miss in gear and vibrates like i have a 15" sub thumping But no miss on our scanner at work. New fuel pump, tps, cap,rotor, plugs, and wires, cts. Any ideas?? Thanks!!

 

This is a '99 right? Have you scanned the computer for trouble codes?

 

Clean throttle body and IAC motor?

 

What vibrates and in what area?

 

It is a 99 and I have checked codes and the other day i got a evap emmisions leak large but i had been experiencing this problem for some time before that code popped up. That seems to
Be the only code in any of the systems on the vehicle

 

I havent cleaned the throttle body since i put the motor in. I will try that for sure! As for the iac motor, i did clean that roughly a month and a half ago but it seemed to have no effect on the issue unfortunately.

When the jeep starts to vibrate, its like the whole jeep starts vibrating like its inside a subwoofer box my mirrors vibrate, my stereo display vibrates (sometimes bad enough i can barley make out what it says) even the rear hatch starts to resonate

 

Ever fart on one? They alert on farts!!!

 

"put the motor in". So you changed the 4.0L? Tell us about the engine mounts

LOL!
Why am I not surprised?

 

I had some rough idle too, I replaced plugs and 02's, clean the throttle body and iac and now it idles 100x better.


I used this video as a reference when cleaning the iac.

 

vacuum leak? you said TPS was new, but can you verify is within tolerance? id second the motor mount suggestion..

 

The motor is out of a rolled 98 xj with under 100,000 on it. I went through it and changed head gasket,valve cover gasket, water pump, alternator, thermostat, oil filter adapter, basically every thing that could be changed aside from internal hard parts. with the cylinder head off we checked for scoring of the cylinder walls and any abnormalities. My boss gave it a gander and looked at the readings on the compression gauge and said it was "beautiful". When i put the motor in i went with m.o.r.e. bomb proof motor mounts which i figured would transfer the engine vibrations through the vehicle a fair amount but this is progressivley getting worse. The jeep has just under 3,000 miles on it since the motor swap...as for vaccuum leaks, i cant seem to find any i've tried dusting the vaccuum fittings with a bit of brake clean to see if it spikes rpm or not.. i got nothing.. vaccuum guage... no drop...I cant verify that the new tps falls with in spec all i can say is that it was a cheap autozone one (i know junk junk) but it seemed to make the jeep more responsive and that it made the idle really steady (it only moved about a 1/16" above 700rpm before, when it was in park or neutral that is)
I think that covers it??

 

Check ignition coil. really look close and run hand over it to check for cracked housing.. As for the vibration, how are u joints? can cause a bad vibe at different speeds..

 

I will check the coil, thats something that i have been tossing around.. if it could be a coil issue that is. The u joints are all brand new, both axles and drive shafts.....and the jeep only vibrates/hums/resonates at a dead stop in gear. any bump of the skinny pedal smooths it right out until it hits that 700 rpm world again.