Car has about 70K miles and has always run well. Had the fuel pressure regulator replaced a couple of weeks ago, and now the engine wants to die at idle. Not every time I stop, but the RPMs will often start to drop; as long as I give it a little gas, it’s okay. The more stuff I have on (heater, RW defroster, radio), the more it wants to die. It’s never done this before. I have to think it has something to do with the fuel pressure regulator, but that’s as far as I can get.
Fuel pump might be getting worn out and not giving constant steady pressure. A quik fix turn idle up a lil by advancing timing may e sure some ppl on here know more a dhave better answer just quik fix to keep running ive done it before to my 85 trans am and 92 camry
I’d clean the throttle body and idle air control valve
Offhand, it sounds like the idle air control valve might have failed
Don’t know year of Focus you’re driving so this may or may not apply. The PCV valve hose where it attaches to intake will get mushy and collapse and start sucking air. Have had a lot of Focuses through the years that had idling problems due to this issue.