H.USA

Thank you very much for your help, After doing extensive researches I learned that on these particular models the 10 bolts on the Intake manifold could be loose so i checked today and they were all loose, I have to admit it was Hell to reach some of the bolts but I did it at the end! Numbers improved, LT is now 3 to 7% while driving it and up to 14% on Idle but I still have to drive it for the computer to learn for some reason I think erasing the Data from the scanner is not erasing the LT fuel memory. If this doesn't fix it I'll go after the gasket and the purge valve. Thank you again!

I also notice a gas cap light on from time to time if that matters

Hello, I have a Chevy Trailblazer 2007 LT 4wd high miles, I have a P0171 and I've been trying so hard to figure it out without going to a repair shop. The Frame freeze data show a P0171 recorded at Coolant temp 206, Idle RPM , LT Fuel trim 26%, the Oxygen sensor and the MAF readings appear normal to me. Live Data now is showing LT 29% on idle numbers improve to below 10% if increase RPM even slightly and get worst very quick on IDLE. I also noticed RPM isn't 100% stable on idle but nothing major. Sometimes the check engine light will suddenly go away to come back later, I also notice a gas cap light on from time to time if that matters I already cleaned Throttle body, MAF , my Air filter was recently replaced. I visually double checked all the air hoses no obvious crack, Breathing cap was cracked so i replaced it but nothing changed. I tried a water test on the manifold gasket but the engine isn't shivering when I toss water, I don't have access to a smoke machine. I can hear a little whistling from the manifold but I'm not sure. couple days ago I had the Throttle body control error but it cleared when I cleaned it and it never came back. Another test of pressing the brakes on Live date show a huge increase in Short term fuel trim to 32.5%. Please help me because The car isn't worth spending thousands on it and it might not even work, is there anything else I can try, is it possible Fuel pump or fuel filter? Thank you so much