Most of the reviews on this product are short and sweet. I want to write a detailed review, to hopefully help many folks out and save their stress levels.We have a 2006 Lincoln Navigator which is also the same as the 2004 and 2005 Navigator models. 150k miles It has the 5.4 VV8 Tritan engine.Our symptoms were high idling, howling sound coming from throttle body, & random what feels like slippage in the transmission. What its actually doing is the engine shifting, at abnormal times. Felt like a jerk etc. Also, the howling sound was only at idle, it would go away, once you started moving. also, our MPG was around 12.7 at its highest.We tried cleaning it a couple months ago and things improved but, got worse soon their after.Now, we purchased this throttle body and the gasket that everyone else is buying with it, here on amazon.Okay, took it to a mechanic/friend to install it and it was quick and easy. However, as many know, the navigator has the fancy engine cover on it and it was already removed. The engine cover may add an extra 15 minutes, to your replacement time. Now, on to the most important step.Once we replaced it, our 2006 Lincoln Navigator displayed " engine failsafe mode " and wouldn't go away and none of the other system settings would show up on the dash. yes, it scares the crap out of you, thinking that you made things worse. As another reviewer stated, it will idle rough, after you replace your throttle body. He hhad the pcm reprogrammed elsewhere etc but, if your replacing it yourself, this would be an extra cost to you.Solution:1. Cut your engine off2. Remove the negative cable from your battery& place a towel or cloth underneath it, to prevent it from contacting anything3. Take a set of jumper cables and use only the black side and connect the negative cable to the posative cable, for 10 minutes. This will drain the pcm settings for your old throttle body.4. disconnect the cables and reconnect your negative cable to the battery.5. Turn off all electronics, air conditioning, car chargers, and recrank your car and let it idle for 15 minutes with no gas, do not rev your engine at all.6. Go for a 15-20 minute cruise on the highway etc and your good to go.If your like us, this will fix all of those problems and our MPG went up to 17 on the highway and it hasn't done that, since we owned it, at 37k miles. It also reprograms your driving patterns and it just drives so much smoother, than before. Trust me, a load has been lifted off our shoulders, thinking we were going to be purchasing a new vehicle. If anything changes, I will update this review.