Alright so I've had my jeep for years and of course it has its problems but this one leaves me clueless. Recently it's been having alot of problems and I'm fairly certain that they're tied together somehow. Alot of times when I start it it's very bogged down and doesn't want to idle (crankshaft position sensor symptoms but it was already replaced) and when I shift into 2nd it is bogged down but then backfires through the intake and after that it's normal. The other day when I started it, it was again idling rough at low rpm like expected but the exhaust was coming out the air intake. I know this because it was very audible and I could see the burning oil coming out. I shut it off immediately and when I started it again it was back to normal. No clue what's going on, PLEASE HELP!!!

Have you done a compression test? You might have a bad valve. Cylinder not sealing, so loss of power, backfire, and maybe backpressure through the intake. That's where I would start anyway.

I guess the first thing to ask is...Check Engine Light come on? Or have you checked for stored codes?

Check engine light is not on and it doesn't throw any codes

I don't have one but I know they're not very expensive so I'll pick one up

Your symptoms sound to be "fuel" related to me. Things I would recommend:

1. Test fuel pressure. You should have 49 psi, plus or minus 5 psi. You really need to start here. It's the most basic of testing data and easy to do.

2. Test your MAP sensor. It is partially responsible for your fuel/air ratio. Be sure that the vacuum line leading to this sensor is in good shape.

Good luck and keep us updated!

thanks for the help

How old are the plugs, wires, cap and rotor? Due to be changed every 30,000 miles.

plugs are brand new but cap and rotor are far overdue

And the wires?

I have no idea when they were replaced last but I've put 15k miles on it and never replaced them.

I'll bet they're as old as the cap and rotor or older. Why not start there? Cap, rotor, and wires. That's normal maintenance that is long overdue.