Do you have to drop the tank in a 90 cherokee to change the lines coming out of it. I have a stumbling problem when you get on the gas hard. So I figure tomorro Ill start with the simple stuff. Plugs ,wires, cap and filters. Maybe those fuel lines and pressure regulator.

 

Change the fuel filter which should be external.

 

Unless a line is pinched/crushed/collapsed replacing them will probably not do much. Change the filter and if you want disconnect both ends of the line and blow it out with compressed air. (be careful not to spray gas everywhere especially in your eyes!)

 

The hoses coming from the tank to the fuel filter are dry rotted and crack. I seen on another thread that if there real bad they may suck air and cause stumbling. Ive been chasinging the cause of the stumbling for about 3 weeks.

I have helped to make it a little better. Routing vaccuum lines correctly and changing plugs. It only does it if you try and give it 50% or more of the pedal.

If you steadly hold 20-30% on gas pedal, No stumble or anything. Makes clean sounding RPMS.

Thats where Im at, so with that it either makes me think fuel system, tps or ign system.

Any Ideas

 

They wont suck air if they leak they will squirt fuel as they are under pressure from the fuel pump. The fact that you say it only does it above half throttle sounds like either the fuel filter is clogged or the pump is going bad as your engine is not getting enough fuel to keep the engine going at high rpm's. It would not hurt to change those rubber lines tho if they look that bad.

 

to answer your original question,the lines can be removed without droping the tank,there is also a small line in the tank that goes from the pump to the outlet,these can leak also. besides checking the things you mentioned,check your cps,it is possible it is going bad.