97 Cherokee dead stock. only needed maintenance parts have been replaced. 4.0 AW4 231. 3.55s, wifes daily driver. 125K miles.
I had an 01 XJ before; same drivetrain, except for a 242 T case.
It was certanly chaper on gas. (I know the T case wont have a thing to do with it just, saying....) maybe it was the coil pack vs Distributor ignition? the 01 did have alot more miles, maybe it was just more "broke in"
loved the 01, til my then 16 yo son rolled it 2 winters ago. so I replaced that one with this 97. the only thing I'd like better, is a 2 door XJ with a 5 speed.
That said, I just had the header (stock) off and welded up a few cracks,
(air leakage messing with O2 maybe?) and I also took the injectors to a Bosch place for a sonic claning off the vehicle. cost $100/set.
that in itself has always made a marked difference in every vehicle I have ever had that done to.

Anyways I see ALOT of web space about swapping to Ford 19 lb (made by Bosch just like our OE ones are) but with a 4 hole spray pattern instead of our single hole ones.
Much of this webspace relates to Dodge 3.9s and V8s as in Dakotas...
Same company same basic system Dodge is known for rich calibrations;
I have (successfully) experimented with other engines swapping different injectors in from stock;
I have also heard that they put "bigger" ones in our 4.0s starting in 97;
and I know that these computers having "adaptive" capabilities that they can adjust the injector "on time" a bit leaving me to believe that it can adjust for a different nozzle to a degree.

Anyone ever play with this on their Jeeps?
I just bought me a set of 8 on Ebay; CHEAP. the same guy has more lo mile takeouts. the set I got coming so far, is going into my 94 Dakota with 2 left over.
If this works out in my Dakota I may try the same experiment in both my 97 Jeeps; my XJ and my TJ.... with gas having jumped $.40 per gallon in the last 2 days I'm just looking to (to paraphrase the old Army commercials) make it the best it can be... for what it is.

 

19lb wont flow enough fuel for a 97.
you need 703s

do a search, this has been gone over so many times its not funny.
Hope you brought your flame suit.

 

I just ordered the "4 hole" injectors for my 01 XJ through precision auto injectors. They sell remanufactured sets for $150. From what I've read on here, it will help with idle and throttle response but any mpg improvements are debatable. Check out their website, some good info on this upgrade.

 

They'll be fine.

 

I put the Ford 5.0's on my '90. Works like a charm.