My engine has started acting a little funny. When I am stopped at a red light, it will start to have sputters of hard idle. I can feel it shake a little, but only for half a second or so. Then after 10 or 15 seconds it will do it again. Sometimes, when the light turns green and I hit the accelerator, it will struggle a little, and I can hear something like a pop. But once I get going, she runs great. While towing a trailer P0301 came on, but then went off shortly after disconnecting the trailer. I have been using Chevron with Techron and adding in some fuel injector cleaner hoping that would fix it, but it hasn't done the trick. Any thoughts on what could be going on, and what to check next?

 

Almost sounds like it happens when your ac compressor kicks on. But, a poor condition will make that initial load worse.

 

Could be plugs/wires, could be bad grounding.

Which engine? How many miles?

 

Check the throttle plate for oil/dirt on it. Clean as needed.
Even if that's not the cause, it's easy to do and probably should be done anyway.

 

08 with 94k 3.8 V6

 

My 09 rubi is doing this too. Dealer tune up did not fix it. 69K miles.

 

Due for plugs and wires by 100,000 miles.

Might want to check over the ground wires.

Is it the original battery? Might want to have it load tested.

 

Clean your throttle body.

Get a can or two of throttle body cleaner & a can of mass airflow sensor cleaner. A rag that doesn't leave lint (like red ones at autozone).

1. Pull battery leads******Important
2. loosen the hose clamp on both sides & Pull off the throttle body tube (do not move or rotate the plug just before the throttle body, see #6)
3. Look at the throttle plate, if you see dark black sooty film...it needs it.
4. spray the outside of the throttle plate, manipulate the throttle plate & open it with your finger. You'll find the back is worse than the front.
5. Spray, wipe, spray, wipe, etc. I have used a flat blade screw driver with a cloth around the tip to get in the places I couldn't with my finger. be sure to get the entire circumference where the throttle plate is in it's natural position. it's where air flows when you are just tipping the throttle.
6. spray the front and back of the MAF sensor in the tube you took off. Do not touch it! make sure it is installed in exactly the same direction so it can continue to function properly
7. give it a couple minutes to air out
8. install the tube as it was.
9. Re install the battery leads
10. It may sound like it is not going to start and/or run rough for a couple minutes. After that you will not recognize your jeep.

Disclaimer: This has worked for me in all of the modern vehicles I drive (Motorcycles, cars, trucks)
In short...thank you ethanol.

 

Well I changed out the Spark Plugs and wires and also put in a new ignition coil. Works great! So far the problem is gone and she is running smooth! Thanks for everyone's help!

 

Had this issue with my 07 JKU @130,000 miles 3.8L automatic and fixed very easily, runs like new. I went on rock auto.com and bought the following:
throttle body
ngk spark wires
ngk spark plugs, iridium
ngk coil pack
a O ring gasket for throttle body
and manifold engine cleaner spray-can

after paying 400 total for parts and doing install on my own the only issue I ran into was the throttle relearn which you can do manually but won’t work half the time. See other threads for details. Took it to a shop they relearned with a computer-free 5 mins total and when I got the jeep back no sputter, no rough idle and fuel mileage jumped 4mpg. This tune up is huge and for me the plugs were at 30,000 miles, coil pack never replaced, wires at 60,000 and throttle body never replaced as well. Jeep runs new now. Hope this helps!