i have a 98 xj and ive got some problems
its hard to start when the engine is cold
it sputters when sitting still
it blows black smoke out the tailpipe when accelerating hard
and i my check engine light is on and the code is po171 which is fuel system to lean bank 1
ive got the 703 injectors and im pretty sure they are good
ive got the e3 spark plugs which are 2 months old
ive got spark plug wires 6 months old
i put a used fuel pump and fuel pressure regulator in last month and they worked fine for about 3 weeks and the all this happened
soooo any help is appreciated

 

How many miles on your engine... O2 sensor sounds like the culprit.

 

Definite 02 sensor, any sudden climate changes where your at, that is notorious with causing faulty 02 sensors, have it scanned for any "PENDING" codes, just so there's no underlying surprises later!! Not to laugh, but its funny the dtc scanner labels it "BANK 1", didnt know a straight 6 had a bank!! lol

 

lol that bank one thing is funny i didnt think about it
but anyway
ive changed both o2 sensors in either november or december and then my check engine light came on an the code was like a p0131 i think
but whatever it was it said the upstream o2 sensor was reading low voltage so i changed it with one i had that i thought was still good but now im guessing it isnt.