Awhile back, about a year ago, the vent valve and the canister were replaced because of code P0496-00. Yesterday the purge valve was replaced because of the same code. Now the engine rpm surges up and down from around 500 to 700 constantly. This surge was not present until the purge valve was replaced. Fuel pressure also goes up and down with the rpm. Am I looking for a leak in the evap system or is there something else I need to look at? I should add the codes are P0157-00, P0171-00, P0174-00, P0496-00. Also acted like it wanted to stall out the other day.
Nov 12, 2026 at 6:48 AM