Originally Posted by dhopson

I have the same problem-P0171 and P0174 codes. No rhyme or reason. One time after 10 drive cycles, the next 1, the next 5, etc... This all started after I had an oil pan leak repaired. The engine was out getting a new gasket set, engine reinstalled and now the codes. Only symptom in the begining was surging when cold-soaked. To date the following has been changed with the problem only getting worse. MAF, IAT, IAC, Fuel Pump, fuel filter, Vapor Canister, 5/8" Vapor Canister Line (kinked), Fuel injectors, and pressure regulator. The EGR was also checked. After all that, it will barely run now. The shop that pulled the engine is getting ready to send it out to a Chevy Dealer to get fixed. They had a "Scan-Man" in and after about 6 hours he gave up. In two of the posts, a prior engine replacement was indicated if I read them right. That could lead to an exhaust leak before the O2 sensors, but they say they have checked that too. Has anyone had any progress yet?

Originally Posted by dhopson

I got my Blazer back last night. They gave up and took it to a dealer. They [dealer] had it fixed in a few hours (I hope). According to a previous post in this string, the injectors are NOT supposed to be grounded at the injector (ground comes through a wire only). The dealer replaced two injectors that were grounded and called it fixed. I have put about 10 drive cycles on it, no SES light yet, but I am not about to call it fixed yet. I checked for codes after I put it to bed and there were none. I am hoping. One note though - yesterday, when I first picked up the car, and a few more times, after first starting it (warm or otherwise) for the first minute (+/-) it did not seem to have any engine power. This morning, it was better. They may have did something that requires a "re-learn" at least I hope that is all it is... Will update final results.