Hi All! I've been a reader on this forum since June 2016 when I picked up my 1994 FZJ80, but this is my first post. Apologies in advance for the lengthiness, but I'm sure the more information I provide, the better you can advise me on moving forward. I got my LC from a local guy who said it had some issues when he got it, and was told his "mechanic friend" put a head gasket on it, and he was only selling it because he needed a pickup truck for his landscaping business. It has 260k miles, zero rust, tinted glass, a clean carfax, and good tires. The hood and RR quarter have really bad clear coat peel. For $2800 and "with a brand new head gasket", it seemed like a pretty good deal. It was running fine when I got it other than some minor vacuum leaks and throwing a knock sensor error(come to find out, there wasn't a knock sensor present which I corrected). I changed the oil and transmission fluid when I got it, as well as the v belts and I'm sure a few other little items that seemed worn out. I also installed an upgraded sound system as I enjoy music and used to be a Geek Squad Autotech(I have my MECP Advanced Certification and am much more experienced with the 12 volt side of things than the mechanical side). Beyond that, I haven't had any issues and have simply driven her a few times a week when the weather didn't suit driving my corvette. The check engine light has come on a few times with the EGR code (71? I can't remember) but i had read here that this was a somewhat common issue that most people ignored. A month ago, I was pulling off from a stop light and I noticed a sudden change in power and a roughness that hadn't been there before. It was very obvious that something was up, but nothing horrific or seemingly serious. I pulled over, looked over my vacuum lines, etc, and didn't see anything abnormal so i kept an eye on my gauges and limped a couple miles home. It didn't have any codes except for "running rich" which lined up with a miss somewhere so I figured that I would do all the "normal" tuneup stuff first since I wasn't sure of the maintenance history: spark plugs(1-4 were a nice tan color, 5 and 6 were slightly fouled), wires, distributor cap, rotor, replaced any dry rotted vacuum lines/hoses, checked for cracks in the main intake hose, etc. None of these helped, and the rough idle and loss of power progressively got worse. I noticed that there was a hidden gap between my air filter housing output flange and the air flow meter(unfiltered air - what the heck), and after doing some research realized that the AFM that was on my truck wasn't the original one - it seemed like it was from a 3.0 perhaps? I'm guessing that the original died and someone pulled something from a junkyard that "fit", but obviously was an issue so i found a remanufactured one on eBay and replaced it. This was over the past few weeks as I found parts and time, and the rough idle and power loss got progressively worse until she started stalling unless i fluttered the gas pedal and now she will barely move around the driveway. I got a compression gauge and checked compression tonight. The dry readings were: 1-167 2-177 3-182 4-179 5-0(oh, crap) 6-0(oh, crap) I've heard that 5 and 6 are classic culprits for head gasket failure on the 1fz-fe. As far as I can tell from several checks, there is no coolant in the oil, and there is no oil in the coolant. She hasn't lost any noticeable amount of coolant or oil. The exhaust isn't smokey, although it does seem a bit moist/sooty(i have gotten a small blue-black puff on startup since I got her). At this point, I'm aware that something internal is majorly screwed up, but my question is what seems most likely? And is it worth investing a potentially large amount of money into the truck at this point based on your experience? Im wondering if the previous guy lied to me and snake oiled the head gasket which just re-blew out, or if theres an issue with the head that caused a legitimate head gasket replacement to fail ~10k miles later. The other thing that seems possible based on what I've read is the valves, but I'm lost on how to test from here to figure out what exactly my actual problem is. I'm VERY good at learning and tackling any kind of repairs and rarely have other people work on my cars, and I have a garage and significant amount of tools, but I don't have experience with something as involved as an engine rebuild. Any pointers in the right direction would be hugely appreciated. I can provide whatever additional details might be helpful!