Between here and r/CherokeeXJ I've received a lot of direct and indirect help and I'm hoping I can pick your brains on something new.

Two weeks ago my 2000 4x4 4.0L automatic transmission XJ with 128K on the odometer started misfiring. The first thing I checked and swapped was the fuel injectors. The car was still misfiring so I splurged on some Bosch 4 hole injectors and still had the same issue. Finally decided to hobble it into the shop... There they replaced the head gasket (definitely blown), resurfaced the head, replaced the upstream o2 sensor and the CPS when it decided it wouldn't crank, and changed out the oil.

Got it back today and there's a ticking noise when accelerating coming from what sounds like right in front of me/my foot area, power locks aren't working, and worst of all the cylinder 3 misfire code popped up after I drove 14 miles shut the car off, drove another .5 miles and turned the car off and on the third start up and .25 miles later got the misfire code.

At this point not sure what else I should do. Thought about getting some heat shield for the fuel rail and injectors? Below is a link to a Google doc that shows all the work I've done to the car since buying it back in April (parts, mileage, date, etc...). Thanks in advance for all the help.

https://docs.google.com/spreadsheets...it?usp=sharing

 

Your xj is a 2000 it should have coil on plug system , have you tried changing the coils ?

 

See if any of these symptoms are happening:
https://www.cherokeeforum.com/how-to...rmation-398176

 

The shop took it apart replaced the head gasket, resurfaced the cylinder heads and said there were no cracks.

 

Standard motor products coil pack and double platinum spark plugs were put in 4k miles ago I could try a new coil pack just to rule it out. Seems weird it would fail within 4k miles

 

TSB #1803103

TSB
1803103 - 4.0L ROUGH ENGINE IDLE AFTER RESTART FOLLOWING A HOT SOAK
Date: 09/05/03 (supercedes 1802702 dated 09/06/02)
Model Year(s): 1999-2004

Description: NOTE: This bulletin applies to vehicles equipped with a 4.0L engine. This bulletin involves the installation of a fuel injector insulator sleeve.

Details: Customers may describe a 20 to 30 second rough idle following the restart of a heat soaked engine. This condition may be most noticeable when the engine is restarted following a prior 10 to 20 minute heat soak in hot ambient conditions of approximately 32 C (90ºF) or higher. This condition may be consistent with short city stop-and-go driving trips and can be aggravated by the use of fuel with a high ethanol content. Depending upon various conditions a MIL may occur due to DTC P0303 - Cylinder #3 Misfire.

This condition may be caused by heat from the exhaust manifold that following engine shut down migrates to the area around injector #3 and causes fuel vapor to form within the injector. This in turn may cause a momentary misfire of cylinder #3 until the fuel vapor is cleared of injector #3. The insulator sleeve lowers the injector #3 temperature to a point below which the fuel will not normally vaporize.

If vehicle exhibits a rough idle, and if a misfire of cylinder #3 is observed following a 10 to 20 minute hot soak, perform the Repair Procedure.

Parts required:
56028371AA Ignition Wire Shield

Repair procedure:
1. Cut insulator sleeve, p/n 56028371AA, to make two (2) insulator sleeves about 25-30 mm (1 in.) in length. See diagram.
2. Install one sleeve around injector #3, with the slit on the upward facing side of the injector. Install the other sleeve with the slit on the downward facing side of the injector.
3. Confirm sleeve is flush to intake manifold surface around injector.
4. Check injector #3 wire and ensure that the injector is rotated to a 2 o'clock position.


TSB for the cold start rough idle and P0303 code: TSB 18-010-01

 

Did you ask if the shop if they could fix this (cause it would seem they could be/are responsible for this).

Since each coil and coil driver controls 2 cylinders, I'd move the coil pack parts cannon to the back of the line. Anyway, for the price of the coil pack you could get an inexpensive diagnostic oscilloscope and test it yourself.

IMO it's prob a fuel injector issue. Borrow the noid lights from Autozone.

 

Does it happen when gunning the engine? Climb in there and look for exhaust leaks. Look for intake leaks. Look for soup leeks.

 

Oh wait NM. I forgot you need the Current Clamp too and that's another 60 bucks.

 

Any type of acceleration will start the ticking noise. This I'm definitely taking it back to the shop for because it didn't happen until they worked on the head gasket.

Coil pack was done myself. But I think I'll try your suggestion of the heat shield. The description you posted pretty much describes the symptoms to a T. If that fails to fix the issue I'll circle back to the coil pack.