Welp heres one that has me stumped. My 96 xj one of 5 has a random misfire one cylinder one and throws the code for injector circuit. But it kinda fluctuates with temperature and driving distance if i go on short rides it doesn't if i go on rly long rides it doesn’t only my everyday commute it does but not always when its cold out it does it more than when its warm and it only does it at idle. The injectors were swapped and plugs were wired in for ev6s before i owned it and i bought it with this problem. I tried new injectors to no avail. Thanks for any help. Fyi 4.0 auto 231 if it helps any

 

Anyone got any ideas anything helps.

 

It could be a faulty wire or connector for that injector, possibly a failing PCM ground circuit, you could try a noid light on that injector, or piggyback some wires and see if the problem goes away

What does that spark plug look like ?