c17loadmaster

Ok so for about 3 weeks now my JKU 2009 has been randomly stalling at red lights. I can't seem to figure this crap out. I maintain my JK very well, regularly change the oil, service as needed, and modify like crazy.

I will tell you what I have (that is relevant) to this problem as far as mods.

MBRP High Clearance Offroad exhaust
Bosch Platinum +4 plugs
Airraid Throttle body cleaner
AEM Cold Air Intake
Using Mobil 1 5W20 synthetic

It regularly idles at 650 RPMs steady, at a stop, with the trans in drive, SOMETIMES it just starts chugging and dies. with no input from me. It should be noted that my JK always diesels when I shut it down (its always done that though) It will continue to run for 2-4 seconds after I shut it down and pull the key out. (weird I know)

I have already cleaned the air filter, changed the oil, changed the PCV valve, cleaned the Air temp sensor, reset the computer (Battery disconnect for 1 hour), removed and cleaned throttle body, checked plug wires (have not replaced yet) and ran a bottle of HEET through a tank to remove any water in fuel.

My next stop will be at the $.50 more a gallon Ethanol free gas station.

I do NOT get any codes, or check engine light. I do not have a programmer (Do have a AEV Pro Cal) I thought it may be the EGR valve, but the associated codes are not present and aside from being $150 bucks, it is a PITA to change since I have the auto.

I have 50k on the JK and need to figure this out. I thought it may be the torque converter going stupid but eliminated that. I think my rings may be going bad, or valves. I regularly use LUCAS in my gas to clean the injectors. I am really at a loss here. If I can't figure this out I may simply trade it in for a new chevy truck. I have invested close to $24K in this Jeep (in mods alone) and it won't even run right.

I can kinda feel a distinct pulse at the exhaust tip, and think I may have a bad cylinder. I do not have a cracked manifold on either side. I already pulled the heat shields and checked. I have the Smittybilt XRC fenders and chose not to have fender liners so engine maint is CAKE without that plastic crap in the way.

I have ordered a Borla Venturi for the exhaust to try and speed up the exhaust velocity right in front of the muffler in order to solve this.

I think a problem may be that the timing needs to be advanced, but since the JK has an ECU is can change the timing as needed. So could a sensor for the timing be bad?

The JK runs great any other time while driving, it only happens when at idle..and only sometimes. So annoying. Please help.

mook8651

How long ago did you put those plugs in an did it start after you put them in? Those motor aren't meant to run with those kinda plugs the best thing to do is put the OEM one back in or buy new ones

c17loadmaster

The plugs were replaced 1k miles ago. The stock ones were burned up. The factory plugs I pulled out were gapped between .5 and .8 and everywhere in between.

rockyjk07

Have u tried running sea foam through it sounds like some sensor might be dirty?

Zombie Hunter

Maybe EGR valve?

ht tp://www.wisegeek.com/how-can-i-tell-if-my-egr-valve-needs-to-be-cleaned-or-replaced.htm

If the EGR valve is stuck open, it will essentially cause a vacuum leak, leading to inefficient combustion, rough idling, hesitation, and sometimes stalling in extreme cases. This is because the car cannot combust on carbon dioxide from the tailpipe — it needs atmospheric oxygen. If the combustion chamber is flooded with exhaust from an open EGR valve, it will not function properly. To check and see if the EGR valve is stuck open, have someone idle a parked vehicle with the brake on while you examine the plunger shaft to see if it is stuck open.

If the EGR valve is stuck closed, emissions of nitrogen oxides will rise, and the car may start to knock. Spark knock happens when the fuel mixture in the combustion chamber ignites before it has been reached by the explosion in the cylinder, resulting in a disruption of the engine timing. In this instance, the engine should be warmed up and revved to see if the EGR valve will move.

Chadc880

I'm also thinking EGR.

But the diesel ing is not normal. Carbon buildup and or incorrect timing yes is a cause, but you need to big deeper. Describe how bad the plugs were ?

I'd also pull the plugs and check your compression on each cylinder.

Noticed any excessive oil consumption ?

What you describe from the tail pipe sounds like a dead cylinder at idle.

Correct me if I'm wrong but does the Throttle by Wire JK's have a idle air control motor anymore ?

TheTerminator

When it starts chugging and about to die, if you give it a bit gas, does it stay alive or dies anyway?

familytime

Did this just start happening or has this been a problem for a while? Look at your plugs,run-ons are due to getting hot.Look at your throttle body for leaks

c17loadmaster

It stays alive if i feather the throttle and keep it from dying.

c17loadmaster

The dieseling has been happening for probably 2 yrs, the stock plugs were gapped all wrong and were blistered. I replaced the plugs but it still happens, maybe even more now