2008 Grand Prix - vibrates when turned off

[tg82]

Guys - any thoughts as to what may cause this.

I'd be idle in park between 500-700 RPMs. When the car is shut off - it vibrates for a second or two before it's off.

A coworker said the issue is "run-off" but i can't find anything on google of use.

Thoughts?

[Engi-Nir]

Guys - any thoughts as to what may cause this.

I'd be idle in park between 500-700 RPMs. When the car is shut off - it vibrates for a second or two before it's off.

A coworker said the issue is "run-off" but i can't find anything on google of use.

Thoughts?

isn't the car under warranty?

[Dina_E]

sounds like a relay problem

its an 2008, dont bother guessing, its should have warranty, let them figure it out.

[fastlayne]

A coworker said the issue is "run-off" but i can't find anything on google of use.

Thoughts?

It is called "run on" or dieseling.

Depending on how the vehicle has been maintained, this may or may not be a warranty issue.

[tg82]

it's under warranty - i'll call the dealership. No cost to me right? (have to ask in true RFD fashion )

[tg82]

It is called "run on" or dieseling.

Depending on how the vehicle has been maintained, this may or may not be a warranty issue.

What do you mean by how the vehicle has been maintained? What risks do I run?

I've only had the car for 2 months now (picked up on April 7th).

[fastlayne]

What do you mean by how the vehicle has been maintained? What risks do I run?

I've only had the car for 2 months now (picked up on April 7th).

2 month old vehicle -- absolutely no risks! Unless you took the car swimming.

I was assuming the worst - 2008 vehicle could have been on the road in September 2007 and by this time could have 60000+ on the odometer.

[tg82]

2 month old vehicle -- absolutely no risks! Unless you took the car swimming.

I was assuming the worst - 2008 vehicle could have been on the road in September 2007 and by this time could have 60000+ on the odometer.

Nope - car was off the production line Dec 2007 - i bought it used with 33k kms on it from a GM dealership. I've just put 3k kms on it since.

[CaptSmethwick]

You don't say if your Grand Prix is the 3.8 or the V8 but I'll presume the former.

If the car just started doing this recently, it could be the batch of gas you have. I'd drive the current tank to near-dry and fill up at a different gas station. I'd recommend Shell, Sunoco, or PetroCanada, buy regular octane and stay away from ethanol for now.

If that doesn't solve it, bring it in to the dealership - it could be a timing issue. Rare with that engine but you never know.

I suspect a bad batch of gas...

[tg82]

You don't say if your Grand Prix is the 3.8 or the V8 but I'll presume the former.

If the car just started doing this recently, it could be the batch of gas you have. I'd drive the current tank to near-dry and fill up at a different gas station. I'd recommend Shell, Sunoco, or PetroCanada, buy regular octane and stay away from ethanol for now.

If that doesn't solve it, bring it in to the dealership - it could be a timing issue. Rare with that engine but you never know.

I suspect a bad batch of gas...

It's the 3.8L. It's been doing it for the past week but i suspect bad gas. The last two fills have been at the local Shell station and their 87 has up to 10% ethanol in it. It's close to empty now and I need to fill up for a weekend trip - i'll put something with no ethanol and see what happens.

[valerka]

try
www.oqcgp.net

[CaptSmethwick]

It's the 3.8L. It's been doing it for the past week but i suspect bad gas. The last two fills have been at the local Shell station and their 87 has up to 10% ethanol in it. It's close to empty now and I need to fill up for a weekend trip - i'll put something with no ethanol and see what happens.

I have no qualms about Shell's gas and the 3.8 doesn't usual diesel - even on an ethanol blend - so there's something wrong. The simplest explanation is bad gas - and that's easily ruled out. Make sure you stick with regular grades. The other causes could be coolant issues (unlikely) or timing. Given that the 3.8 uses a steel chain, rather than a belt, it might have been from a bad batch and has stretched. Again, unlikely but not unheard of.

I really do suspect the gas.

[skidz88]

Does the car have electric motor mounts?

[CaptSmethwick]

Does the car have electric motor mounts?

Never mind: Googled it - this is a Nissan VQ thing. The GP does not have them.