I have a 2007 jk auto and recently changed the plugs, wires and oil. Shortly after, my engine started to vibrate while idling at stop lights. I work at a car dealership (but not a jeep dealership) and asked a mechanic to look at it. He seemed to think it may be a compression issue because he checked for vacuum leaks an came up empty handed. He said it could be a rod but wasn't sure. Anyone experience anything similar? I brought it to jeep and of course they said my power train warranty expired at 36k. The dealership by me sucks so bad that one time, the told me they didn't know what was wrong with my jeep, said they couldn't fix it and forced me to pick it up broken.

So my question is; do I pay someone to tear it apart and fix it, do I replace it with another 3.8 or do I upgrade to a better engine. I am on a small budget and really can't even afford to have had this happen but here I am....please help!

 

Exact same issue I have been dealing with on my 08. No answers for you but subscribing to this thread!

 

Hemi time!

 

I have a similar issue, but it isn't constant. Only every so often does it rattle while idling. The mechanic said possible compression issues. Did you or him check the compression at the cylinders? Did you clean up the throttle body? Have you checked your fuel pressure? Before going and diving into new engine, or having this one tore apart, I would do some of the simple stuff first. Air, Fuel, and Compression tests. Or just try some fuel system cleaner first and see if that helps.
One thing I forgot to add: Do you use a tuner, like superchips? If so, reset it back to stock and see if that helps

 

if it was running fine before u changed plugs and wires dollar to a donut bet its a loose wire or a bad or improperly gapped plug recheck everything its probably nothing major

 

I had this happen on a honda. when I watched the car run in low light, you could see a spark jump from the pug wires to a ground point in the engine bay. I changed wires and it stopped. Maybe try putting the old wires in temporarily.

 

Definitely double check the plugs and wires. If it was running good before hand it's probably something you did. Not trying to be mean, cause I've done it also and I'm a mechanic by trade.

 

Thanks guys. I installed E-3 diamond fire plugs and drove the jeep the following day with no problems. The following day I did get gas before this problem started...but being the paranoid non-mechanic, mechanic I automatically assumed it has to be plugs or oil. So I returned the E-3's and installed Champion Double Platinums along with new wires. Recommended gaping was .47-.52. Mine were set at .5. The problem still remains so I'm off to clean the throttle body, check the fuel pressure and compression at the cylinder. I'll let you know what I find out.