4.0 liter

I'll be driving along with the engine hot and it misfires under steady throttle causing the whole car to jolt. The tach needle drops a few hundred and then shoots right back but there are never any codes. This problem has been happening over the past couple of years, it'll misfire here and...

Just picked up (2 weeks ago) this 2004 TJ-X (Columbia edition). This is my 4th jeep (JK, JKU, JTR), but my 1st TJ. I plan on doing most of the modifications myself so I hope everyone here is ready for my questions. I've been scrolling through the build threads, started at the oldest & working my...

TLDR: I discovered metal flakes in my oil during a routine change; not chunks or shards, more like glitter. Engine has no noticeable abnormal knocking or dieseling while running, and idles very smoothly. Oil pressure gauge (no numbers, just dots) sits just above mid-line at idle, pressure...

Good Morning Guys, i have a buddy that is getting rid of a 2002 4.0L motor due to coolant in the oil. motor was pulled and a full swap was done on his. so the motor has harness, ecu, and complete 141k motor. I have a 99 with somewhere around 170k 4.0. Both motors were/are paired to 5 speeds...

I had the hood open today, adding a secondary return spring to my throttle (it's a 2005 4.0L and only had the onboard/inline spring) as a short term experiment. I was poking around, looking at the vacuum lines just to understand where everything connects. I've never really paid attention to...

Hi all! 2006 Wrangler 76k miles on the 4.0l. Automatic. I bought it 6 years ago when it only had 15k. It came with a 2.5" Teraflex lift and some other suspension upgrades but was never off-roaded. We've been driving it lightly ever since. It really drives great. Soft top is original and has...