93 wrangler spits sputters and backfires sometimes ,them will take off and run fine ? Has over 130000 miles on it , is in good shape . Has 4.0 in line six cly. will a elec. fuel pump cause this?

If you have not replaced plugs start there A bad map sensor will also cause black smoke and poor running

if its back firing u have a timing problem

have the fuel pressure checked,the fuel pump may be going out.

Check EGR value, clean or replace. Also PCV valve replace it is cheap.

I would first begin with a good tune up with new plugs wires cap, rotor, check coil. injector can be clog also, try to add bottle of fuel injectors cleaner and add 93 octane of gas fill it half way and run it til empty and see that will also help. If you have high miles like over 100k have timing check, its good idea to change timing belt every 75-10k miles, if it jump time due to worn belt, the car will not run properly.

Have you had fuel pressure tested, and/or filter changed. Have you checked for plugged exhaust, such as catalytic converter? Quite often engine will also run a little hotter than normal when exhaust is plugged.

I have the same problem on my 95 grand cherokee laredo. Sometimes it starts out fine and after about 10 miles it starts spitting and sputtering. Then after a while it seems to clean out and run fine again for a little while. Then other times it starts out spitting and sputtering at the begining. I changed the fuel filter and that was not it. It is a 4.0L 6cyc. Any Ideas?

Thanks,
Broken Arrow, OK

sounds like a ignition problem, try new cap rotor and wires and plugs if this does not fix your problem it is either your coil or distribitor

is engine light on. if so get code might cat conv not letting enough out. allowing to much backpressure

have you checked firing order on plug wires? could be problem.