.Full Disclosure. I did a full throttle body cleaning where I removed the bodies, did the toothbrush cleaning on both sides of the butterflies, changed all spark plugs with OEM and all coil packs with after market. I did the three reprogramming steps to the best of my ability using Youtube videos.

My '08 G37s has now developed a stutter at low rpm around 45mph and easily felt with the seat of the pants. I checked the torque on the plugs, the throttle bodies to see if I slipped that gasket, put the original coil packs back in, all to no avail. No error codes are throwing. I am at a loss. I finally took it to the dealer. They say I have a "Faulty Valve Body" which I assume is means throttle body.

How do you make this diagnose with no error codes, is one question I have? Did I somehow damage one of the throttle bodies while cleaning it? I did not disconnect any wires but did manipulate the bodies while cleaning them.

Looking for wisdom. Thanks in advance
David

 

Are you for sure you did the pedal dance correctly? Plugs to the throttle bodies are tight and secure?

Valve body = transmission. Highly doubt you need a new transmission if you just did a cleaning. I'd give the TB re-learn procedures another go.

 

 

This comment might not serve of any good but I can easily clean my TB's without disconnecting them.

I had this issue hunt me on my old g35 and ever since I've not had to electrically disconnect them to perform any service.
The pedal dance works for some but it's a waste of time in my opinion.

 

If it started after the maintenance I'm guessing the aftermarket coils are probably bad at least one .or the gap in the plugs is off. Not sure how they where installed but it's never a good idea to just drop them in as the gap might close a bit as they hit . doesn't take much to pressure to close the gap

 

When it comes to ignition, OEM is typically best. If the coils weren't bad, why did you replace them? That's a lot of money to drop on something not necessarily needed. Z1 sells their own coil packs now and those are the only ones I would purchase besides OEM.

 

I did replace all the coils and plugs just because the milage. 150,000.

I did put the original coils back hoping that would correct the issue, which it did not.

the dealership wants $2150 to change out the transmission part. Seems way high.

 

Yeah I'm not sure how this is transmission related. Might want to clarify with them exactly or get another opinion.

If you suspect the throttle bodies are bad, or one, I'd pick up a used cheap one on ebay and swap it out.

 

The dealership is saying this with no error codes. This surprises me that a full engine stutter does not give some kind of code. It is frustrating that a new auto valve is a $300 full retail part and that the dealership wants $2100 to install. Have not found a video on how hard or easy it is to install and program a new valve for the transmission. I have already paid full labor charges to them, and the issue was incorrectly diagnosed and not fixed.

 

So what was the issue?

 

It has been over a full week, and no phone call from the dealership. That tells me that their remedy did not work.
Need some advice here. I want to call and be straight forward with them. I want to say that the transmission valve was not the culprit. I do not want to pay for that expensive part but will compensate the technician for his time???????

In the mean time, I still do not have my beloved car back.