As some of you already know, I started getting codes P0171 (system too lean â?? bank 1) & P0174 (system too lean â?? bank 2) back in early January. At first, I reset the CEL, but they both popped up again two days later.
Since it was freezing cold out, I was hoping for warmer weather to arrive before I tried to diagnose the problem. Well, as the weather got colder, the problem got worse.
A few times the car stalled out immediately after starting it up. And a lot of times the car would have a hard time idling after startup in the cold weather.
I tried spraying carb cleaner on the engine seals and found that the engine stumbled when sprayed around the UIM gasket.
Well, I replaced the UIM gasket last Sunday, and the codes haven't come back.
Since the UIM was off, I looked around and found that one of the secondary linkage grommets (aka UIM linkage retainers) was missing, which meant that only half of the secondaries were opening!
Anyway, I just wanted to report that a P0171 & P0174 can possibly be fixed by checking for a bad UIM gasket.
