Test Your Lean Condition P0171 / P0174 Diagnostic Skills!

You are a national treasure sir. I have been watching you videos for a couple years now and always learn something new. You present data in such a great manner to teach people.

Matt, I want to sincerely thank you for making this video series! I have a 99 Silverado NBS with the 5.3L. I've been trying to troubleshoot the cause of my P0171/P0174 for 2 months (due to lack of time and money). This series really hit every possibility, in the fastest and cost effective way, and you are a true "troubleshooter"... and that comes from a guy who is a troubleshooter on fighter jets. 2 days after watching the entire series and taking lots of notes (like you said, don't just stop when you find 1 possible issue) my truck was fixed! and I don't have any of the cool toys you do. THANKS BUDDY!!!

Great job explaining fuel trim and problems. Thanks!

Hi Matt, a fantastic video, I have liked a lot of the questions during the diagnosis, this time you will overcome. Please, I would like to do more videos like this. Thanks Master, thanks for your time and for sharing your knowledge with us. Thanks Matt.

most common problems with po171 dirty maf, fuel delivey and vacuum leak. freeze data show the problem is only under load that eliminates vacuum leak. the problem only affects 1 bank which eliminates dirty maf and fuel pump. o2 sensor shows rich at wot and switching normal. I would check fuel injectors on bank 1 with a fuel injector pulse tester and check that each injector delivery the same amount. thanks for your videos I learned so much from them.

I just had had a toyota with both banks STFT at 8 and LTFT at 52 and P0171 & P0174. Turned out to be a piece of fuzz wrapped around the MAF wire. Removed the fuzz and a shot of cleaner and instant fix confirmed on scanner graph. I used all of Schrodingers thought processes to get to the MAF. Thanks Mr Schrodinger. Might I add that AZ free scan wanted the guy to buy a $110 O2 sensor before he brought the car to me.

it's 2 am and i can't stop watching this channel, damn you mat, greetings from argentina

thanks for all the great videos and all the different ways to look at them keep up the good work.

If I suspect a part is the problem I usually check it with a multimeter where applicable and I clean sensors, check vacuum lines etc. Need to watch this one a few times Matt and I am going back over the fuel trim videos too. Great channel.

You're a great instructor. I got the right answer right off the bat! But, I didn't watch your fuel trim videos multiple times. Repetition is good for old dogs.

I was a GM mechanic for 20 years and had a wonderful time, all i did was short blocks and engine rebuilds, I was the only guy on the line who like doing them and i got extremely good at one point, I was young enough to install manual transmissions without the need for a transjack, just pick it up and slip it in. BUT But but....When i had to learn an all cars later, I was spoiled and had no experience, I got over it, but was never as good with any other cars, Nice video.

The best educational youtube channel I have found on diagnosis cars! Great channel wowwowowow thankss

This is a good example of why not never just go off a trouble code and always look at relative live data for other clues.

That scotty kilmer choice though....... 😂😅😂😅😂

i just found your channel while trying to fix a 5.7 that hesitates. i like your format (instructor giving quizzes) and you are quite entertaining. keep it up! ever spend some time with performance Audi products? be careful, I used to think American muscle knew no equal. rs7 Performance Premier made me reconsider. being a physician you are able to test drive one without being an imposter/ tire kicker. do so. Those Germans are pretty sneaky a 4 door super car, its almost criminal.

I love all of your videos that I've seen, but the graphical representation of the "ricer flyby" made me laugh out loud. Just one more reason I love watching these.

Matt. Your a great tech. I enjoy watching you troubleshooting. All your videos are awesome. Don't be a parts changer.

Trust me. This is not wasting my time. Your videos are golden.

Awesome video, always learning something new from you. 👍🏼

I enjoy the amount of knowledge I obtain from your videos, they've actually helped greatly getting my grandpa's truck running again. Favorite parts thought are you jokes about that Terd with lips scotty kilmore