LiamLikeNeeson

1989 Cherokee 4.0L I-6

Last night I was checking out a tip I got to check the transmission fuse because my backup lights don't always go on and so I pulled it out and and ended up looking at the wires under the dash just out of curiosity and there used to be a phone installed in it that I took out and found the wiring that was connected to it led into a bundle with some other wires like the cruise control wires (a 15 fuse ended up on my floor and don't remember taking one out to replace a 15 fuse and checked to make sure all the 15's were there and they all were so that was quite odd). After, I started my jeep and I backed it up and stopped in my driveway when I noticed an odd rumble that is very noticeable. I got out and listened to see if there was any odd shaking in the engine and there wasn't but I leaned over towards the 6th cylinder as I was trying to follow the noise, it was over cylinder 6 and then I checked to see if anything was leaking and nothing was but I was hearing an odd whistle from under the engine (purge hose from the cylinder whatchamacallit that's under the heater core hoses?) and I was leaning on the body while bending over while checking for leaks and I felt the rumble and followed it to the lift gate where the vibration was very noticeable at the area right above both taillights and so I listened to the exhaust and it sounded the same as it did before the rumble. It's starting idle is normal at about 750 rpm and while in park I tapped the accelerator and when I released rpm would drop to 250 then back up. After a while, when the engine gets past 150 ish degrees, the vibration starts to go away. I do need to get gas because the light just went on on the fuel gauge. The CPS and ECM were replaced just a little over 2 months ago and the CPS was replaced with the better quality one and not the one that goes out easily. I hope all of that isn't too confusing. Thanks.