Hey guys! Got an inquiry! So I've got a 98 XJ 4l Auto with 240k! Outside of the fuel gauge not working, It runs like a champ, perfect startup, minor idle roughness, all electric components work, it's basically a unicorn. Except.... I've got a slight random hesitation under acceleration once to 3 or 4 times a day. Now here's the situation:

Fuel pump, fuel injectors, spark plugs, ignition cables, distributor cap, intake, throttle body, cam position sensor, crank position sensor, throttle position sensor are all BRAND NEW
Now the hesitation/buck doesn't happen at any specific rpm, speed, distance/time driven, temp, etc but seems to happen more often the warmer it is out. For instance I'm here in Nashville, TN and I can't recall it happening more than a couple times if at all Nov-Jan.

My initial thought was Torque Converter since I do hear a slight rattle upon startup under the trans where the torque converter resides and I know that bolts can bore out and loosen over time. However I don't wanna believe it's that cause that's not a job I'm capable of doing within my current residence (apartment living).

So my question is, having replaced everything I thought it might be, what else could I be missing? I have a Fuel Circuit "A" Code that's been on since I got it a year ago (attributed that to the reasoning for my fuel gauge not working), but it throws no other codes and even after replacing the fuel pump that code persisted.

Ok, so lemme have it and don't hold back.

 

Checking/tightening the flexplate to torque converter bolts is not a big job.
Have you ever cleaned your throttle body and IAC?

 

The IAC and Throttle Body are brand new. One of the many things I replaced trying to fix the issue so I'm pretty sure that's not it. And as far as tightening the flex plate goes, I've always understood that you have to drop/lower the transmission the get to torque converter. Am I wrong? Please elaborate cause I would love to be wrong!

 

So it seems I am very wrong! Hazaaa! So I'm gonna try that out and get that tightened up. Do you think that could be the issue causing the hesitation? One thing I forgot to mention is that I do have a bit of a crack in my headers right at that lower bend. I wouldn't think that'd be the cause of the hesitation but I've clearly been wrong before soooooo?

 

Weird question because of similar sound situation. what do you mean by hesitation? my jeep used to have a hesitation, sometimes flat out stalled. most innocuous solution.... loose wires at battery. tightened everything up and it's right as rain

 

So by hesitation I mean like a buck. At any moment, as long as my foot is on the throttle, it can just jar or buck, but then everything's fine after it has it's little fit. Sometimes it can happen a few times a day, sometimes not all.