Why Would My Jeep Die / Stall & Does Not Have Acceleration Or Power To Go Over 45 Mph

’90 Jeep Cherokee (not a grand) 4 liter 6 cylinder

I was having a lot of problems with it not starting and with it dieing once it started, so I replaced the fuel filter and still had the problems so I replaced the fuel pump and cleaned all the spark plugs. Wow what a difference! The Jeep ran great for about a week or two and then slowly I started having other problems, Jeep dies when coasting down hill (I shrugged this off as no big deal popping it into neutral and starting it right back up) Then the Jeep started to act like it was losing power while going down the road but always recovered and drove fine. This started happening every time I drove. The Jeep also had a very slow crank when starting, it would act like the battery was dead but then would start right up. (not cold outside battery not dead) When driving the Jeep it runs better if i put it into neutral and keep it at a high RPM while braking. Also once I get going down the road it tops out at 45 MPH and stays at the same RPM (unless put into neutral of course) I’m not sure what RPM it’s topping out at, just don’t remember.

I researched a lot of possible things, the list of what could be wrong with Jeeps is endless it seems. If you can rule out something for me or send me starting in the right direction it would help. I’m 19 and don’t know much about working on vehicles but I’m learning & I want to do my own work and need some guidance.
– rotor, cap, coil, crank shaft position sensor, engine control unit, crank angle sensor, wires, plugs, oil, battery, idle control valve, need to clean throttle body, need to clean injectors, relays, check 20 amp fuse for the ECU from the panel under the hood, MAP sensor, Idle air control sensor, Idle air motor sensor, Idle air control valve, throttle position sensor, do a fuel volume check find out what the pump should be pumping in 30 sec or 1 min…, O2 sensors, heated O2 sensor, catalytic converter, cam shaft position sensor, vacuum leak.

but if one of these things were the source of the problem wouldn’t it come on suddenly? Not slowly… With the exception of the idle air stuff and the vacuum lines.
Could there be something lodged in my fuel line? Lodged in the pump? (the gas tank is FULL)

I think I’ve found place where part of my vacuum line is missing, small black tube sucking in air, what now??? How do I figure out where it’s supposed to go? How do I find the vacuum line schematics for a 1990 Jeep Cherokee and how do I read them?

Additional note: My Jeep has for a very long time had a high idle problem, idles up really high sometimes when i put it in park. This comes and goes and to me isn’t a big deal. Is it possibly related?? I’m thinking Idle air control here.

Thank you for reading this, any advice, help or guidance is really appreciated. Or if anyone could rule out some possibilities from the list I’ve composed that would be a huge help as well. Again thank you for reading and replying.
I doubt it’s the starter I already replaced it not long ago

Answers for The Question

  1. Wilfred Fizzlebang
  2. LOTUS
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