Hello all how's it going? Hope your all doing well. I'll try to keep this as simple as I can. I have a 4.0 convertible stanger and I just got a new 70mm throttle body from bbk. I installed it and after I did my car started shaking and idling weird. I did a little research. I know about the spring that has to be rotated 160 degrees into the 2 slots. And I know about checking the voltage. Here is my main problem. I had a tune done when I put on a cai and I never got the voltage readings for the old throttle body before I installed a new one. Would my voltage readings change with a tune? Will my car just rough idle until I can get a new tune? I know for a stock mustang it's suppose to be between 1.19 and 1.31. are the numbers diff for a convertible mustang? And would my numbers be different from stock since I had a tune for the Cai? Also can I return the car to stock hook up the old throttle body and get the reading then? Or is it just trial and error at this point. I was able to get the voltage to 1.25 it worked fine for a sec then when I turned the car off and wait 5 min and turned it back on the throttle started acting funny again. Just trying to see what my options are at this point. I know this is alot but I appreciate any help. Thanks again.

 

I'd start out by re-flashing back to the stock tune with the stock throttle body and stock airbox and get the voltage readings.. If that resolves your rough idle issues? then you'll know it's either the BBK throttle body or the aftermarket tune..

Also, if the CAI has a larger mass air flow tube housing over the stock diameter MAF tube? then yes, your numbers will in fact be different and require an aftermarket tune for the aftermarket CAI.

It would also be in your best interest to contact the person who did your tune about the rough idle issues your having, as he would be the best person to troubleshoot and help resolve your issues..

Meanwhile, best of luck and hope everything gets straighten out.