Alright so I got a 1985 Jeep pioneer 5 speed 4x4 it’s all stock and I recently bought it for 400$ it sat for 2 years and the last owner said there was nothing wrong with it when they parked it but obviously from it sitting it needs some love to get back on its feet. When I first started it, it didn’t wanna stay at a normal idle. It would go from 10 rpms to 20 and just sat and bounced in between. So I adjust the idle a little bit and now it stays idle at a constant rpm of 18-20. But anytime I press the gas it bogs out and then when I go fully to the floor it drives like what seems like it’s supposed to. Also my oil gage sits at 80 always

 

My first reaction - Bad gas - 2-year old fuel probably has some water in the tank and the pump sent it to the injectors. Siphon it out of the tank and get some fresh fuel. Second reaction - A stuck IAC (idle air controller). What you need to do is either free it up (internal cleaning), or replace it if cleaning doesn't get a good idle. That said, you need to 1) undo what you did to get it to idle at 1,800-2,000, as close to the original RPM you started out with as possible, and then 2) address the IAC. Do that in that order. Also, the tachometer reading you're calling out (RPM) is 1,800-2,000. The engine's normal idle is around 700-750. I don't have the precise RPM. The IAC was probably working properly when the seller was using the vehicle but sitting for a couple years probably let the internals of the IAC to corrode and seize. If that cures the low idle problem but it wants to run like crap, put a can or two of injector cleaner in the tank. Start with the RPM readjustment back to where it was originally and bad gas possibility.

 

A 1985 would be a carburetor, no IAC. Here's a quick writeup on adjusting the idle. https://itstillruns.com/adjust-idle-...e-6785793.html

Bad gas or a gummed up carb seem likely. Fuel injected is much more tolerate of bad gas than a carb'd vehicle. Given the age, I would carefully inspect all of the vacumn lines for leaks. Look through the wiring for rodent damage. The wire to the oil pressure gauge might be broken or disconnected.

 

In addition to the above, a dirty throttle body could also be part of the issue (assuming it has one?) The good thing is they are easy to clean.