MUSTANGEXPERT

I just had my engine rebuild about 2 months ago and i went to the dmv to get my car inspected. they told me to come back after i drive 200 miles because the system is saying that my car is not ready? Is this right do i have to drive a couple hundred miles before its ready??

dysan

It does take a while and if you have a custom tune installed, your rear o2 sensors are also probably turned off so you have to speak with your tuner about getting an emissions tune also.

Art161

From the 2007 Owner's Guide (probably the same or similar for 2006).

If the vehicle's powertrain system or its battery has just been serviced, the on-board diagnostics system is reset to a "not ready for I/M test" condition. To ready the on-board diagnostics system for I/M testing, a minimum of 30 minutes of city and highway driving is necessary as described below:

First, at least 10 minutes of driving on an expressway or highway.
Next, at least 20 minutes driving in stop-and-go, city-type traffic with at least four idle periods.

Allow the vehicle to sit for at least eight hours without starting the engine. Then, start the engine and complete the above driving cycle. The engine must warm up to its normal operating temperature. Once started, do not turn off the engine until the above driving cycle is complete.

Mikes_BLK_GT

Its most likely the tune, as stated above get an emmisions ready tune.

zkiller

You need the rear O2 sensors on. You will never pass without them on.