97 XJ 4L stutter/misfire on cold start

Now that i have some money in my pocket im sorting the kinks out on the XJ i had to buy in a pinch last year.. did a fuel module, new CTS, replaced the "cold air" retrofit with a stock box and put in a CAT/O2 sensor because the PO removed both. Now im learning as i go, this is the first vehicle ive ever worked on.. I also plan to do a piece by piece lift and etc down the road but priority 1 is getting her back to running right.

Now to the problem at hand, on a cold start, it will Misfire/stutter maybe 5 or 6 turns of the crank, so like 3 or 4 seconds? and if i dont let it warm up and go to drive away, it will do it sporadically until shes warm. Now i think i have a leaky injector (probably more than 1). I still have an overheating problem but only when its been at low RPMs for a long time (driving downtown for a half hour she gets super hot) thats probably a fan clutch or bad waterpump.

could it be that im getting heat soak and theres no liquid gas in an injector until it cycles out? Also it JUST started doing it after i got a CAT and 02 sensor in the back, maybe the #1 02 is starting to go?

lots to digest here but i appreciate the help, any similar stories?

i put a new atk in my 2000. ever since it has a similar sounding issue. runs rough for a few secs then is good untill i leave it sitting somewhere for a few hours. mines clears up under load. swapped out ALL my injectors which did nothing. cps, crank, nothing. still trying to figure it out.

Did you reset your adaptive memory when you installed the new o 2? Any engine codes?

^ should note that when I reset my comp it clears up for 3-4 days before returning. dont get ur hopes up like i did haha

The start up symptoms are similar to a faulty fuel pump check valve. Did you install a new fuel pump assembly ? Did you install a Bosch, genuine Jeep, or some cheap junk like Airtex ?

Leaky fuel injectors can also causes similar symptoms.

Resetting the Adaptive Memory does not identify or cure the root cause.

Do you use the headlight trick to empty the memory though? On top of just disconnecting the battery there is a procedure for clearing the memory

Tim_MN said:

The start up symptoms are similar to a faulty fuel pump check valve. Did you install a new fuel pump assembly ? Did you install a Bosch, genuine Jeep, or some cheap junk like Airtex ?

Leaky fuel injectors can also causes similar symptoms.

Resetting the Adaptive Memory does not identify or cure the root cause.

Click to expand...

No I did not install a Bosch or OEM, I dont remember now what brand, ill have to call the part store because my receipt doesnt list it either. Thing is they're listed as a 4x4 shop and a few mechanics RUN xj's.. www.modernmotors.com ALSO, NO shop will rent a fuel pressure gauge, the cheapest is 60 bucks, I can get new injectors off ebay for 100.. frustrating as a broke ass student

Choosing quality brands is probably the most recent thing I have learned, and will consider in the future, I just did the fuel pump in early August FYI.

I've been out of town for 2 weeks and just got home, my fan clutch is bad, which is probably contributing to the heat problem..

altrocker1 said:

Do you use the headlight trick to empty the memory though? On top of just disconnecting the battery there is a procedure for clearing the memory

Click to expand...

I Didn't even know this existed, ive always just unplugged the pos+ terminal to clear the codes... I'll look this up now and do it. Thanks man

ANOTHER thing that i just realized driving home last night, the jeep is still backfiring on some shifts, it didn't even dawn on me that its odd because i was so used to it.. so im thinking my #1 02 sensor is sending false readings? Does that make sense?