I have gotten my first Xj it is an 89 Cherokee Laredo 4.0L AW-4 Np242 with just a touch over 125,000 and i have a couple of issues I'd like some opinions on to see if i am heading in the right direction first off i have a slight miss fire so i replaced the plugs wires cap and rotor. nothing fancy ac-delco plugs and cap and rotor and wires from advance auto. still missing so my dad thought that it was cam issue pulled the valve cover and all valves open and close as they should only issue is that the lifters on number 2 cylinder had a lot of side to side movement to them when tightened down. But no bent push rods or anything like that. I am wondering if it could be electrical related Tps, Iac, ground refresh? Or maybe a clogged injector i ran some Lucas fuel system cleaner through it though, kinda thought that would rule out a clogged injector.
My 2nd issue is with my wipers they are the delay wipers but they are only working on the high speed setting. Sometimes if i let them go for a few cycles on high i can turn them to low or a delay setting and they will work, sometimes not. I also noticed that the park feature in the wipers doesn't work if they are straight up when i shut the switch off they stay that way. Is that a sign for a bad wiper motor or is that the delay box going/gone bad?

Thank you in advance and sorry for the lengthy post

 

Did you mean rocker arms instead of lifters on #2 cylinder? I would use Champion copper plugs instead of the AC Delco's. Your jeep has a fuel filter under the vehicle that is pretty easy to replace. That might help too.

 

Yes i did mean rocker arms. Apparently wasn't paying too much attention to what i was typing LOL
. I did read about the Champion Coppers after i put the AC Delco's in and Haven't checked the fuel filter

 

When you checked the rocker arms did you do it only one time in one position?

 

I have a 99 xj with a id plate fastened to the front bumper that looks just like a vintage muscle car fender id tag.

It has 7 potential lines of data.
------------------------------------------------
line 1 - x member 4d 522688
line 2 - blank
line 3 - blank
line 4 - mwg end
line 5 - adl aht cuf k2z lcd ldb
line 6 - xjjl74 pq7 qq7 m5az
line 7 - u erh dgb xl641133 6135
------------------------------------------------

can anyone decode this for me or send me to a site or reference so i could do it myself.

 

mdnov No i took the rocker arms and put them back on the NO 4 cylinder they still have a lot of side to side movement i am thinking they are worn out. didn't actually get to see if the miss followed the rocker arms back to NO 4 yet

DavidWaller i am wondering if a Jeep dealership could decode that for you

 

The reason why I ask about the rocker arms are that when the cam goes around there are highs and lows. If there is no pressure from the cam lobe on the push rod, the rocker may be a little looser than one that the cam is on the hight point of the cam, if that makes any sense to you. I would disconnect the battery and have someone turn the motor over by hand. It is easy to do by turning the bolt that holds the harmonic balancer on.

 

it makes sense i'll have to try that test and see what the results are.