Misfire in cylinder 5

Lifted straight six

TJ Enthusiast
Joined
Oct 26, 2020
Messages
106
Location
arizona
Hello, I have an 02 4.0 that I have come to some very weird issues… I replaced the harmonic balancer, as well as the entire cooling system… When doing this, coolant went everywhere when burping the system, today… I washed the engine compartment, drove it, and low and behold… a pending 0305 cylinder 5 misfire code… Never popped up, but was pending via OBD. Code has not came back since. I thought I may have got something wet, so I got home, reset PCM and dried it off very good with towels, and a hair dryer. My question is…

Could I have messed up cylinders causing misfire with the harmonic balancer change? I had the belt on and tried tightening it, motor moved a bit.. I also had my OBD scanner hooked up, and I noticed my calc load % to be higher than usual, used to be around 17% all the time, now jumps around from 5% at idle and anywhere between 20-50%. My Fuel system always used to say CL, now it will say OL-drive and OL from time to time, seems to run decently fine.. Is this all normal? Where do I start?
 
Hello, I have an 02 4.0 that I have come to some very weird issues… I replaced the harmonic balancer, as well as the entire cooling system… When doing this, coolant went everywhere when burping the system, today… I washed the engine compartment, drove it, and low and behold… a pending 0305 cylinder 5 misfire code… Never popped up, but was pending via OBD. Code has not came back since. I thought I may have got something wet, so I got home, reset PCM and dried it off very good with towels, and a hair dryer. My question is…

Could I have messed up cylinders causing misfire with the harmonic balancer change? I had the belt on and tried tightening it, motor moved a bit.. I also had my OBD scanner hooked up, and I noticed my calc load % to be higher than usual, used to be around 17% all the time, now jumps around from 5% at idle and anywhere between 20-50%. My Fuel system always used to say CL, now it will say OL-drive and OL from time to time, seems to run decently fine.. Is this all normal? Where do I start?
Correct me if I am wrong, please… but… after some calm and collect logical thinking I have came to understanding more of how to read the OBD(I always used to just wait till it popped the light) but I am a little more preventative now.

I realized that I completely swapped a fan clutch from a “HD” to a mopar extreme fan clutch. This to me already tells me it should have higher engine loads than I had before(cooling system is working great btw!)
When I was reading my “Fuel system” tab in the scanner I realized that immediately after I start the jeep, it will be on OL(as it should until it warms up) Once thermostat kicks on and I am at a steady speed of 55, it doesn’t change from CL. It only changes to OL-drive when I decelerate or accelerate(I also believe this is how it should technically work)
I also have driven the jeep about 30 miles since I cleared the misfire code, has not came back yet after the good dry/sitting in the AZ sun for about an hour. It has also seen speeds up to 65ish, no evident power loss, although A/C stops blowing hard after speeds of 60, which to me seems like a vacuum issue that I have to deal with next.

Does this sound correct and normal? I do not have a clue what anyone else’s TJs run in the OBD scanners, so if any of what I said that I believe to be correct is incorrect please… CORRECT ME! Any help would be much appreciated
2002 4.0 I6
AX-15 5 Speed trans
(swapped from nv3550)
35 inch tires
4.88 gears