Rough idle, need advice

[RJ787]

Well fellow GT350/R enthusiasts, need your expertise opinions. Went to take it out for a short drive. Put some 93 octane per usual, then when I pulled out of the gas station the car just felt “different”. Engine pressure was at 30 at idle, so figured that can’t be good? Drove it very gently back home. Dipstick oil level picture below, oil reaches bottom of the picture. Engine temp was around 216. Car has 9,285 miles, all street miles, never had any issues. It was around 81 degrees outside. Still no check engine light, but doesn’t look normal. Still under factory power train warranty till August 2025.

Edit: After reading online, 30psi at idle seems normal. It would go up to 100psi while revs increased. The dipstick oil level still seems concerning.

Edit #2: update in post #30, re titled thread

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[MAGS1]

Well fellow GT350/R enthusiasts, need your expertise opinions. Went to take it out for a short drive. Put some 93 octane per usual, then when I pulled out of the gas station the car just felt “different”. Engine pressure was at 30 at idle, so figured that can’t be good. Drove it very gently back home. Dipstick looks like below, oil reaches till bottom of the picture, engine temp was around 216. 9,285 miles. Still no check engine light, but doesn’t look good. Still under factory power train warranty till August 2025.

Edit: After reading online, 30psi at idle seems normal. It would go up to 100psi while revs increased. The dipstick oil level still seems concerning.

Were you able to repeat the oil level on the dipstick several times in a row after letting the car sit for a few minutes? After driving, that first pull can have excess oil up the dipstick tube from driving, as I’m sure you already know.

Did you notice anything else when limping it back home? Any colored smoke coming out of the exhaust? Any weird smells? Any weird noises or vibrations?

Also, if you have an OBDII code reader, might be worth plugging it in to see if the car is throwing any codes (may not necessarily trigger a CEL). If your car is connected to FordPass, there’s a vehicle health area in the app. Something might show up there too. Ford just pushed an app update yesterday that has some new features that expands on the vehicle status/health features of the app.

 

[RJ787]

Were you able to repeat the oil level on the dipstick several times in a row after letting the car sit for a few minutes? After driving, that first pull can have excess oil up the dipstick tube from driving, as I’m sure you already know.

Did you notice anything else when limping it back home? Any colored smoke coming out of the exhaust? Any weird smells? Any weird noises or vibrations?

Also, if you have an OBDII code reader, might be worth plugging it in to see if the car is throwing any codes (may not necessarily trigger a CEL). If your car is connected to FordPass, there’s a vehicle health area in the app. Something might show up there too. Ford just pushed an app update yesterday that has some new features that expands on the vehicle status/health features of the app.

I didn’t try the dipstick again, something came up but I will try it again tonight. There was no smoke, no oil is leaking. All seems normal, it just felt “different”, not sure how to explain it other than it was a rougher idle, not excessive though. Maybe it was in my head. Just checked the FordPass app and nothing is showing up. It is due for an oil change though. I don’t have a scanner but might pick one up this weekend. Thanks @MAGS1

 

[MAGS1]

Amazon has those scanners pretty cheap. Not a bad idea to have one on hand anyway. Good luck, let us know if you get one and if it pulls any codes. Always unsettling when the car feels different that’s for sure

 

[Inthehighdesert]

Sure you didn’t get bad fuel?

 

[RJ787]

Sure you didn’t get bad fuel?

Could be, but I always fill up at this gas station (BP) as it’s the only chain that carries 93 octane in the Kansas City area. I will do a follow up test drive tomorrow and update.

 

[MAGS1]

Could be, but I always fill up at this gas station (BP) as it’s the only chain that carries 93 octane in the Kansas City area. I will do a follow up test drive tomorrow and update.

BP is typically where I go as well. Never had an issue with their 93 but I suppose a bad batch is possible.

 

[Kabayo]

Well fellow GT350/R enthusiasts, need your expertise opinions. Went to take it out for a short drive. Put some 93 octane per usual, then when I pulled out of the gas station the car just felt “different”. Engine pressure was at 30 at idle, so figured that can’t be good? Drove it very gently back home. Dipstick oil level picture below, oil reaches bottom of the picture. Engine temp was around 216. Car has 9,285 miles, all street miles, never had any issues. It was around 81 degrees outside. Still no check engine light, but doesn’t look normal. Still under factory power train warranty till August 2025.

Edit: After reading online, 30psi at idle seems normal. It would go up to 100psi while revs increased. The dipstick oil level still seems concerning.

Hard to see the oil line on your pic. Is it up to the lower hole on the stick?

 

[PoCoBob]

You said you pulled the dipstick, but didn't say whether you wiped it clean and then checked the level. If you just pulled it out it's going to look way over filled.

I think what happened with the rough idle is some fuel got into the internal vent tube when you fueled up. My Edge does this quite a bit. If I fill up and then have to stop before I can pull out of the station, or have to stop at a traffic light within the first block the engine will stumble while idling. Once I go a few blocks that vent seems to clear itself and it doesn't happen again until the next time I fill up and the same scenario happens.

 

[Postal Bob]

Could you have possibly overfilled the gas? You know, once the gas nozzle shut off, you tried to add a litle more? You might've splashed some gas into the vent hole of the filler tube. That could cause a stumble when you get going, or come to the first red light. It usually goes away right after that.
Also, when you check the oil, wait about 5 minutes after turning off car. Pull the stick, wipe it clean, then insert it again. Then pull it and read it keeping it level. If there's oil in the first hole you're gtg.

 

[RJ787]

Hard to see the oil line on your pic. Is it up to the lower hole on the stick?

Yes it all the way down the bottom picture.

 

[RJ787]

You said you pulled the dipstick, but didn't say whether you wiped it clean and then checked the level. If you just pulled it out it's going to look way over filled.

I think what happened with the rough idle is some fuel got into the internal vent tube when you fueled up. My Edge does this quite a bit. If I fill up and then have to stop before I can pull out of the station, or have to stop at a traffic light within the first block the engine will stumble while idling. Once I go a few blocks that vent seems to clear itself and it doesn't happen again until the next time I fill up and the same scenario happens.

I forgot to wipe it and re-measure it, rookie mistake as something came up while analyzing it. Will redo it tomorrow and update. It was 25 to empty and I added $25 of 93 octane.

 

[RJ787]

Could you have possibly overfilled the gas? You know, once the gas nozzle shut off, you tried to add a litle more? You might've splashed some gas into the vent hole of the filler tube. That could cause a stumble when you get going, or come to the first red light. It usually goes away right after that.
Also, when you check the oil, wait about 5 minutes after turning off car. Pull the stick, wipe it clean, then insert it again. Then pull it and read it keeping it level. If there's oil in the first hole you're gtg.

I forgot to wait and I also didn’t wipe it and re-measure it, now I feel like an idiot.

 

[PoCoBob]

now I feel like an idiot.

Don't. Good on you for noticing something is different in how your car is running and looking for something wrong. Lots of people would just keep driving it and then say they had no idea what happened if something did go wrong.

 

[UpACurb]

If you have to ask if your engine failed.....it probably didnt fail.... just saying : )

I and many of my friends have....ummm.... turned connecting rods into disconnecting rods via a viewing portal in our blocks....or turned our motors into "knock knock" jokes....

I guess its easier to joke about it when its just a small block Ford/ GM lol

When you break it - you will know/ hear it - it wont be a question ....

25 to empty and you added gas...then it didnt run right...my guess is bad gas also...

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