rough idle/vibration

[CAgilbuena]

Any luck? i've got the same issue at idle. I'm beginning to think it's a fouled plug. Got some hesitation sputtering on an uphill climb. Going to inspect the plugs in the morning.

 

[Lancaster]

Thanks for the response. There is 80k on it.

Thought 1: My experience is that 80k is too much for these plugs/wires. I did mine at 105k. The origional plugs were well worn - the only electrode remnants being rounded little nubs. The wires were brittle.

Thought 2: night and day difference when MAF and TB are cleaned.

Thought 3: please discard the k&n. My experience is that they wreak havoc on intake electronics ultimately costing you more in diagnosis fees than OE filters and the hp gain, especially on an SUV, are imperceptible.

 

[992dr]

Any updates?

OE plugs typically last 100k miles. I'd read them before replacing them, same goes for the wires.

K&N gets a bad rep because of the miss use of there products, basically over oiling them. They make great products that last as long as you maintain them properly. This miss use also effects the MAF as well as the TB. You do not use liberally, use sparingly and give it an adequate amount of time for the oils to settle into the filter.

It wouldn't hurt to clean your MAF. Be careful when cleaning your TB as its drive by wire.

 

[mjwills]

I took it to an independent shop. They replaced the exhaust hangers and the vibration is 90% gone. - night and day difference. I guess the exhaust mounts were all worn. Not to sure why the dealer didn't replace that when they had the exhaust off. Now I still feel something, but was in a friends Denali today and feel the same thing. They confirmed that engine and trans mounts were fine. My initial question is what is causing the exhaust to vibrate that much to begin with. They think it is originating from the trans (see below).

I still think there is something loading the engine, but this shop went through everything and it all checked out from a mechanical standpoint.

I still have a droan at 1800 RPM. When putting scopes on it, there is excessive noise coming from the middle area of the trans. How do I prove that to a dealer?

 

[Lancaster]

I took it to an independent shop. They replaced the exhaust hangers and the vibration is 90% gone. - night and day difference. I guess the exhaust mounts were all worn. Not to sure why the dealer didn't replace that when they had the exhaust off. Now I still feel something, but was in a friends Denali today and feel the same thing. They confirmed that engine and trans mounts were fine. My initial question is what is causing the exhaust to vibrate that much to begin with. They think it is originating from the trans (see below).

I still think there is something loading the engine, but this shop went through everything and it all checked out from a mechanical standpoint.

I still have a droan at 1800 RPM. When putting scopes on it, there is excessive noise coming from the middle area of the trans. How do I prove that to a dealer?

Set the dealer's expectations by requesting a test drive with you as the driver. Fill them in on the history so they know what is going on. They never look at the history. If you are lucky enough to get a good tech or service manager, you should be in good shape.

 

[YukonXLPerk]

Motor mounts?
A broken motor mount will cause the shaking you are experiencing.

The idle moving up and down a little is normal. The computer will increase the rpm slightly so that it will not stall when your accessories place a load on the system.
Search the forum about this problem. Some of us have sworn to have found a fix for this.

 

[ccapehartusarmyINF.(ret)]

usually to check the the motor mounts have someone in the drivers seat put in gear while holding the breaks giving it a little gas while you watch with the hood up to see if the engine moves excessivly make sure you dont stand infront though lol

your definatly correct on the misfire codes in fact fords actually have to have so many misfires continuously right in a row before the PCM throws a code
im tottally with you on your gripe with the so called certified technicians
im actually curious what makes them certified because i spent almost two years at UTI
in there auto\diesel and ford fact program and i even found some time in there to get a couple asc certs knocked out and i dont refer to myself as a certified technician
is there some special GM certification corse?

 

[harveje]

We've changed plugs, wires, injectors, cleaned the TB, MAF, seafoamed, etc..etc... still have a miss. I've put a tech 2 and no codes, mis fires, etc... still chasing the rabbit..

 

[mjwills]

Bringing this up again as I am still chasing it down. I have new motor and trans mounts and front hub bearing going in this week. If this doesn't solve it I am at a loss.

Jumping ahead, but the vibration goes away if I put it in neutral and if in gear and brake torque it I can get the sound/vibration around 1800 RPM. If the mounts do not fix this, could there be an issue in the torque convertor? Is that in motion once the car is in gear? Do trans/driveline issues through codes? (I have not seen any).