Recently my fiesta has been dropping revs when at idle after filling up and when my gas tank gets low any ideas as to what’s going on? It drops down to about 700ish then shoots right back up. I also usually fill up on 87 if that makes a difference
It’s the evap system. The ultimate fix is to switch to the pre-2015 evap lines and an aftermarket intake elbow.
It’s your evap purge valve. It’s a common issue—search for “purge valve” here, and you’ll find all the info you need.
It’s the purge valve, though I forget the exact name, lol. Mine does the same thing after getting gas and has been doing it for 2 years.
Mine does the same, I’m running 91 and completely stock. Sounds normal to me.
If you have a heat gun, just grab the valve. It’s an easy swap.
Welcome to being a Fiesta owner, lol! Looks like it’s time for a purge valve replacement.
It’s the EVAP valve. If you have a heat gun, the part number is C1B1-9G866-AA. You can find cheaper copies on Amazon for about $15 if you’re up for a DIY fix.
Alternatively, you can go OEM for around $100 plus shipping from Tasca or other online parts retailers.
I’m going the DIY route since these seem to fail often, and the hose is usually fine. Honestly, mine has been doing this since new, and I have 96k miles on it. I just keep the RPMs up to about 1,200 when I’m stopped for 3-4 minutes after filling up. It never bothered me enough to replace the valve—only doing it now because I’ll be down there working on the transmission mount.