digger90

has anyone ever had the problem of driving the jeep for a while at operation temp, get to your destination and shut it off. 15-20min later go out to start it and it has a misfire for a min or 2 then clears up. usually happens when its around 85+ outside.

y does it do that?
how can that be fixed?

ptonjeep

is one of your spark plugs goin bad

lonewolf411

Same thing happens to me. I really want to know why and what i should do to fix it. Its so annoying

fishtaconc

Any specific cylinder? tripping codes? Im thinking possibly injector getting hot. I see you have a 01, try searching injector heat shield.

2000'XJ

I have a 2000 and have the same issue. I have found running higher octane fuel to lessen the problem. My guess would be denotation due to high cylinder heat and low octane fuel or ????.

tjwalker

00 and 01 4.0 XJs are especially susceptible to HEAT SOAK.

Search for lots of light reading.

There actually is a technical service bulletin from Jeep on this.

digger90

no changed them last summer

digger90

i wanna say it was #1 or #6. had the p030? code for misfire

fishtaconc

This is what i was trying to say but I was trying talk to my 2yr old and wife kinda got distracted.

tjwalker

This is heat soak, almost assuredly.

Fixes range from the lame Jeep TSB fix where you put a blanket around the #3 injector, to hood louvers, to a timer which keeps the e-fan on for a while when you shut off the engine.

The e-fan timer is a good one to consider and seems to have good success.

I've included the TSB, but know that this fix works for very few people. It was a feeble attempt by Jeep to resolve this.


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.