On the highway I can step on the gas pedal and I feel a heavy vibration from around the gas pedal area. I can feel it above the gas pedal and on the center section to the right of my foot near the air vent. I have no idea what's causing this...I can feel it a lot when I accelerate in the firewall and pedals...thinking it might be a leaking exhaust? Let me know what you experts think

 

how much tread do you have left on your tires?

 

How long since you had your Z aligned and the wheels balanced? Having the wheels balanced will also tell you if you've got a damaged rim, which can also cause vibration, although a damaged rim usually feels more lumpy to drive.

Just a couple of ideas.

 

If the vibration is intense AND only happens when you step on the accelerator, I'd have the engine and transmission mounts checked.

I'll sometimes feel a very slight harmonic around my right foot at some engine speeds, but I don't think that's what you're talking about.

 

You should have everything we said checked

 

What kind of exhaust are you running?
Any test pipes or HFC's?Small crack in the welds could cause this.

 

Tread is pretty thick, got the wheels balanced a few times and happends even with an alignment. I don't think any of the wheels are bent. Transmission mount was replaced even though the old one was ok. Not to sure about the engine mounts, they are not leaking and look ok...have stock exhaust

 

Might have to bring it to the dealership (I say that because they know about Infiniti)

My steering wheel also shakes really bad, which everyone online says that is a wheel balance issue, but the wheels have been blanced a few times. My steering rack is a remanufactured rack that was replaced last year. I can turn the wheel to the left and it will never bottom out just keeps twisting. Not to sure whats going on there but that's another issue.

 

Thats probably the issue right there ^

 

HAHAHAHA That must look so funny if you could mess with a passenger... just keep turning the damn thing
never hurd of that happening tho

 

Well there is a bunch of feedback, but as I turn the wheel it seems like I am just twisting the rack when it is supposed to stop

I don't see how a sloppy steering rack could cause this vibration. Is there something you can put in the engine that will leak out of the exhaust if there is a leak? Kind of hard to find a leak in the header area

 

If your car has a clock spring behind the steering wheel, it's probably toast.

Is the wheel always in the same position when you're going straight ahead?

Sounds like whoever replaced your rack did a really sloppy job. If the teeth on the rack go past the teeth on the pinion (that's what lets the wheel spin), they probably have the adjustment threads on the tie rods bottomed out on one side and barely engaged on the other. That's a potentially dangerous situation that may lead to loss of control.

I'd have that dealt with immediately, if I were you. The entertainment value isn't worth the risk.

 

This ^

 

Hahaha I replaced the rack...I tied the steering wheel in the straight position while replacing the rack, but still couldn't get it to equal wheel turns when left and right...it's difficult to center the rack. Have any tips for doing so? I'm going to get a replacement since I have a 3 year warranty on it.

 

Did you look in the service manual?

 

The service manual only gives a mm measurement of the rod that comes out the passenger side of the steering rack. Can't exactly measure it with the rubber boot on, but don't want to void the warranty by taking it off...maybe I should check with the company with the other one they are sending.

I have also seen online to center the rack by counting the turns and dividing by two.

 

Thinking back to the few racks I've seen taken apart, there wasn't any way the rack could travel beyond the end of the teeth, since the teeth were cut into a rather hefty round bar. When you got to the end of the teeth, the pinion hits the bar, and can't turn any more. Teeth would have to be completely missing or worn down for what you describe to happen.

Hopefully you won't have the same issue with the next one.

 

If I turn full right the rack bottoms out abruptly (like a bump stop) and if I turn full left it doesn't bottom out it just gets very hard to turn when it should stop and sounds like something is crunching in there !

There is a squeaking sound in the steering wheel when I turn it so I'm sure the clock spring is messed up, but would the clock spring cause the steering rack to malfunction? Or the steering rack to cause the clock spring to malfunction?

 

Just called the company who sold the rack from ebay and they said they need a mechanic to call them after they diagnose the issue. I have no idea why the rack will not bottom out when turning it to the left. They think it's strange that it does that

 

The clock spring is just wiring to the control buttons on the steering. It can only turn so far before it breaks, but that won't damage the rack or cause a problem with steering the car. Does the horn work?

There is some adjustment available in the rack to set the tooth engagement, but I suspect you got one that's worn beyond the limits or damaged from an wrecked car.