Leaderboard

Any joy with this truck seems to be short-lived. The CEL for P0172 ("bank 1" too rich) is now "intermittent". I'm not sure where to check, or re-check, and my energy to keep chasing problems with junk is wearing thin. The P0172 seems to set as I'm coming to a stop, completely off the throttle, when fully warm. At least, that's what it's done the 3? times it's set. Everything appears normal on the scanner EXCEPT long term fuel trim. There's only one bank on this vehicle because it's an OBD 1.5 with only one upstream O2 sensor. At idle, it's around -16.4% and will dip to -18% occasionally at idle or off-throttle. LTFT approaches 0 when throttle is held at 2500rpm. Short term appears normal, much closer to zero all the time. The LTFT tells me the engine is running rich at idle but compensating at higher load. But, why? The EVAP purge valve doesn't appear to be leaking/sucking fuel vapor continuously. Is it sticking just as I come to a stop and the engine is choking on fuel vapor and sets the P0172? But that doesn't explain the persistently negative LTFT. Disconnecting the purge valve doesn't seem to make any difference. I suppose that leaves another dang issue with the fuel injector. A leaking fuel pressure regulator, a new leak in the spider, or a leaking fuel injector/poppet valve I didn't see, or a small crack in one of the spider legs. The vacuum line leading to the fuel pressure regulator doesn't have raw fuel in it. It doesn't even smell like fuel when it's pulled off, not until you suck air through it, then you can tell it leads to a fuel component. I'd consider that normal? Nothing is signaling this is a FPR issue from the outside, at least. The oil smells like fuel but it's not building volume. I've noticed most oil in most engines smells like fuel to some degree so it's hard to say if the smell is an issue or not. Or if the engine just still smells like fuel because the crankcase was full of it a few hundred miles ago. But it's been changed twice since that original issue of the leaking fuel line dumping fuel into the intake. Patience is running very thin. Every win seems to be accompanied by two steps backwards, or another issue that leads to removing at least the top half of the intake manifold. Enough! LOL