I have a 2006 H3 with 3.5 5 cylinder. I have a misfire at idle. I had loose intake bolts so I replace intake manifold gaskets. I cleaned throttle body, checked spark plugs, performed injector balance test, moved ignition coils around, it has a 6 month old battery that test good, charging system is within specs, cleaned battery terminals and checked grounds, ran compression test, all cylinders around 180 psi. The misfire is only on cylinder 4 and only happens at and idle. Checking PIDs with Snap-On scanner show miss goes away at 950 RPMs. Can anyone point me in the right direction to solve this issue. The VIN is 868323045. I think this is outside the TSB range for head problems.

 

Welcome to HF.

The New Member section is strictly for hello introductions, not Tech Questions. I made your duplicate disappear from the General Forumes and I MOVED this for you to where ALL H3 questions go...................................... in the H3 Section.

Scan and Post all codes. If you are still using the crappy azzed OEM Battery Terminal Connectors, get rid of them for a quality aftermarket set like Stingers or your favorite brand, #1 mod to be done for every H3/H3T.

Until then, might want to take a look at this, this is the list for a rough idle. Acts like it wants to stall/rough idle -No CEL -What To Do:

 

I realized I posted in the wrong place after I posted it. New guy clicked wrong heading and didn't notice.

 

This doesn't try to stall it just has a misfire at idle. I have a snap on scanner and I can read the misfires and RPM at the same time. The misfire goes away at around 950-975 RPMs I've checked everything in this thread-Acts like it wants to stall/rough idle -No CEL -What To Do: didn't make any difference.

 

Very similar to what I am experiencing on my '06. Looks like we posted pretty close to one another, maybe an hour apart. Misfire at Cylinder 4, sits directly below in the intake. I have not had a chance to perform a compression test, but am headed that way myself. Good luck!

 

You covered a lot of your bases so far. That by the way is refreshing.

I've heard of people having good luck with top end cleaning via a product like seafoam directly injected into the TB via hose. There are other products to.
I've personally started to research this and it really does seem to help.
You may have carbon build up.

Of course it could also be a different thing all together.

 

Including???????????????
If the problem still persists:
6) Pull the camshaft actuator solenoid and look for crud on the sensor, on the screen in the motor, or a missing screen... replace if necessary, tighten mounting bolt to 10 N.m/89 lb in.

 

yes cam actuator too

 

Take a look at post #8 in this thread? 06 / Rough idle, CO277, CO240, multiple misfires

 

Sent truck to dealer, the called and said it had a burned valve. Has anyone seen an engine with a burned valve have good compression?