Happy New Year Scotty!
I am dealing with codes P0171 and P0174 on my van. I've replaced the pcv house and valve, egr valve, dpfe sensor, vapor canister vent valve, and MAF sensor. I haven't done a smoke test but I've checked vacuum lines and I'm not seeing issues. What common problems have you seen that cause these codes?
poor fuel pressure
I need a button on my keyboard that just types this.
Is this from a bad fuel pump? I can hear hissing like a vacuum leak but can locate it. Despite the new EGR, I sprayed carb cleaner around it and the RPMs did increase.
you definitely have a vacuum leak then.
I thought you said you checked and didn't find any.
I haven't done a smoke test but I checked the hoses and they all seem fine. Wouldn't spraying the EGR cause an increase in RPMs anyway?
noooo.... EGR should be sealed.
Spraying anything except directly into the intake should have no effect
Thank you and pardon my ignorance. This is a brand new one so I didn't understand why it would do that. New stuff is faulty sometimes too.
Well I found that the gasket on the EGR wasn't installed correctly. That's been repaired and P0174 is now gone. P0171 remains. The line from the throttle body to the purge valve has been replaced because it was collapsing. However, the new one seems to be doing the same. I may opt for installing a 90 degree vacuum fitting to reduce the turn that causes the line to slightly kink. Any other ideas? It's shuddering when accelerating but seems to idle ok. No more RPM increase when spraying carb cleaner in the engine compartment so the EGR issue was fixed with the gasket.