Loose steering wheel + "pop"

[Voltwings]

So, as the title states, i am trying to diagnose a pop in the steering wheel when gassing through turns, and will try to provide as much detail as possible below.

1. the K-member has been dropped by a shop to install headers... i think the problem started when i got the car back, but i really cant remember since it took a while to notice it, the problem does not happen every single time.
2. There is a slight (but noticeable) amount of slack in the steering wheel; basically i can jiggle the steering wheel with no movement of the actual wheels. I have compared with other mustangs and mine is noticeably more loose. Car has 20k miles and no wrecks.
3. When the popping occurs it is not only audible, but i can feel it in the firewall / through the gas pedal
4. The car is lowered on OEM boss shocks / struts / FRPP K springs
- I know some people mention the top hats / perches need to be replaced when lowered, but i have a feeling this is a different issue
5. i have gotten under and tightened / double checked every single nut / bolt i can find and they are all tight
6. If someone is in the car jiggling the wheel, you can slightly hear it where the steering shaft exits the firewall in the engine bay.
7. The pop is consistent throughout the turn, not just a one time thing, and stops once the steering wheel is moved back towards the neutral position.


Possible thoughts:
1. The steering shaft is hitting the Kooks shorty headers when turning and the motor is torqued? I think i really only notice it on left hand turns (including a high speed corner at my recent track weekend, as well as around town, it is not speed dependant), but i have no idea how hard / far the motor torques when turning or on the gas. The kooks headers also look like they have plenty of room under the car.

2. K-member / steering rack no realigned properly? It really looks like theres only one way for it to go, and even if it was off, it doesnt explain the slack in the steering wheel.

3. basically the only thing i can think of is a damaged steering rack? What else would cause slack and whatever the hell is popping like this?

I'm tired of trying to figure this out and would really appreciate some help. Thanks.

 

[ArizonaBOSS]

Either the rack is somehow offset, the steering shaft is hitting the headers under load, or they didn't properly torque down the U-Joint in the steering shaft.

 

[Voltwings]

Either the rack is somehow offset, the steering shaft is hitting the headers under load, or they didn't properly torque down the U-Joint in the steering shaft.

How can I check if the rack is offset? I checked if it was loose, but don't recall any sort of "alignment" markers. Granted, I wasn't looking for them.

It is possible the headers are hitting, but I feel there is a decent bit of room still, and it doesn't explain the slack in the wheel.

I have tightened every bolt on the steering column (that I can find) as tight as I am comfortable, so I think I can rule that out... kinda leads back to number 1, but again, doesn't really explain the slack in the wheel?

 

[Voltwings]

Is this the U-joint? I feel like if i hold that lower section with my hand (to hopefully keep it from moving) and have my girlfriend jiggle the wheel, there is a slight bit of slack in the steering column. A very slight amount though... i doubt its enough to be the same amount of slack i feel in the wheel. Besides, its hard to see, but it looks rectangular. I imagine it will only fit in there one way?

Edit: well ... i cant figure out how to attach a photo, so i'm guessing this post doesnt make a whole lot of sense.

 

[ArizonaBOSS]

There are 3 joints in the steering shaft system. One inside the cabin behind the wheel, and two in the engine bay. Check all of them.

Here is some further info and a diagram: http://iihs.net/fsm/?dir=801

 

[Voltwings]

There are 3 joints in the steering shaft system. One inside the cabin behind the wheel, and two in the engine bay. Check all of them.

Here is some further info and a diagram: http://iihs.net/fsm/?dir=801

Thats awesome, i'll take a look this weekend. Thank you.