H3 engine gremlins

[H3slate]

I have a 06 H3 adventure w/ manual trans and 100k miles. I am having some noise and vibration at idle. The tach does not move, but there are noticeable shudders felt in the shifter and steering. I can also hear the change in the engine. It is not consistent, it is random and doesn't happen all the time. Under acceleration and at speed the truck feels fine. Only other symptom is when trying to accelerate at low rpms. Usually in 3rd, 4th, or 5th, if I am less than 2k rpms, the truck struggles to accelerate and feels like it is hesitating. Once above 2k it is fine, or if I down shift it accelerates fine. The check engine light has not come on during this. Even if I sit and let it idle for awhile with the odd vibrations it doesn't throw a code. I average 15 mpg with 35" tires and a roof rack. I have not seen any change in my mileage while this has happened. I have replaced the spark plugs recently with no change.

Any ideas on what the issue could be? As bad as this sounds, I keep waiting for it to throw a code so I can at least have a part or system to focus on. I am considering replacing the coils to see if that helps. I had previously replaced coil #2 to clear a p0302 code. The other coils are still the originals.

Any help with this would be appreciated.

 

[deserth3]

Check the heat shield between the exhaust manifold and the first cat. This would be a fairly rapid vibration and is load/RPM dependent.

 

[H3slate]

Check the heat shield between the exhaust manifold and the first cat. This would be a fairly rapid vibration and is load/RPM dependent.

I have looked at the heat shield and tried to address that issue with bigger washers. The heat shield rattle is a lot different from the noise/vibration I feel through the transmission.

 

[TAPDH3T]

I have the same exact issue and I'm under 30,000 miles lol.. I have looked every were and can't find the rattle and the idle does the same thing. It's not all the time and if I put it in park it stops most the time..

 

[H3slate]

I have the same exact issue and I'm under 30,000 miles lol.. I have looked every were and can't find the rattle and the idle does the same thing. It's not all the time and if I put it in park it stops most the time..

I guess I wouldn't categorize my issue as a rattle. It does not sound or feel like a loose shield or part. It feels more like a hesitation, shudder, or vibration through the engine and transmission.

I have replaced my motor mounts recently due to wear, but did not affect this issue.

 

[TAPDH3T]

I guess I wouldn't categorize my issue as a rattle. It does not sound or feel like a loose shield or part. It feels more like a hesitation, shudder, or vibration through the engine and transmission.

I have replaced my motor mounts recently due to wear, but did not affect this issue.

I have that same issue.. I think my rattle is coming from my spare tire holder. I don't have my spare on there and the mount is dangling.. I tried to zip tie the little spring still but I feel there is still movement...

 

[SuperBuickGuy]

Have you scanned for codes? not all codes will send a CEL, and you can see what the sensors are seeing with a scanner (it's how I diagnosed my MAP sensor's problem - a P0121 code with intermittent CEL).

 

[cbetts]

Mine had an intermittent stutter at idle before I cleaned the throttle body. I tend to suck a lot of oil through the intake from high RPMs and steep hills.

 

[H3slate]

I checked the throttle body when I changed the plugs. It had a little bit of oil that I cleaned up, but looked good.

 

[H3slate]

Finally got a code to show up when I was airing up my tires. P0301. I have a new coil on the way, already replaced the spark plug.

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[alrock]

It's rare when you can celebrate a code, it's nice to have a targeted solution. Fingers crossed for you!

 

[SuperBuickGuy]

oil on the inside - do you have a K&N or similar filter? if so, you need to clean your MAF sensor with MAF sensor cleaner.

 

[H3slate]

oil on the inside - do you have a K&N or similar filter? if so, you need to clean your MAF sensor with MAF sensor cleaner.

The oil was from the vent tube that connects just before the throttle body.

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[H3slate]

Replaced the ignition coil on cylinder #1 and truck is running better. No more erratic idle, and smooth acceleration.

 

[alrock]

Woohoo!

 

[cbetts]

Sometimes the gremlins are the simplest things. Glad to hear you got it fixed!

 

[06 H3]

Glad to hear its working well again. I replaced one of those about a year ago. The first coil had water intrude and rusted it out.

Everyone should check those every year or so now that our trucks are getting older and see offroad abuse

 

[4speedfunk]

Lucas fuel system treatment. Its like magic in a bottle. No bull...try it.

 

[H3slate]

Lucas fuel system treatment. Its like magic in a bottle. No bull...try it.

I will check that out. My mileage went up 1 mpg after the fix.

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[M22KLARS]

Mine had an intermittent stutter at idle before I cleaned the throttle body. I tend to suck a lot of oil through the intake from high RPMs and steep hills.

I'm amazed that you guys aren't running an oil catch can inline there. I was running one for the last month or so that I had my H3 and I was catching quite a bit of oil.

 

[alrock]

Been waiting for you to come down and install one for me

 

[cbetts]

I'm amazed that you guys aren't running an oil catch can inline there. I was running one for the last month or so that I had my H3 and I was catching quite a bit of oil.

You have my attention. Got a web page reference?

 

[Kyle]

You have my attention. Got a web page reference?

+1.

 

[06 H3]

x2. Im interested.

 

[alrock]

Try googling "oil catch can". :wink: There are lots of universal kits that you can attach that help catch oil that makes it out of the PCV and into the intake. Anyone ever taken apart the intake resonator and seen oil in there? That's what the catch can is designed to catch. The catch can becomes a maintenance item as you have to empty it from time to time, but that's not a difficult thing to do.

[video=youtube;DJ7Z2F51fzs]http://www.youtube.com/watch?v=DJ7Z2F51fzs[/video]

Back when I was having engine issues (pre-cylinder head diagnosis) you could practically pour oil out of my resonator. Might be the same way now; haven't checked it :emb: