Intermittent rough idle

[fms 19’ Gt]

I’m curious if anyone has experienced or diagnosed the potential cause for an intermittent rough idle while in drive or sports mode with a gen 3 coyote that has an automatic transmission. It probably started about 5-6 weeks ago for me. There has not been a single check engine light or code stored within the system. But between one to two times a week I’ll be cruising around, approach a stoplight and while I’m sitting there the RPMs will drop to about 400 and the engine will shake a little bit then jump back up to normal idle range, & won’t happen again for a few days afterwards. There’s been one instance where it’s happened while in park & that was about a month ago. Earlier this week, I had an instance where it actually became frequent during a drive-through downtown but once I turn the car off for a while and came back, it didn’t happen for another three days. I’m just very confused and would appreciate any reply and knowledge on the subject thank you in advance

Sponsored

 

[ORRadtech]

Does it happen to coincide with a fuel fill-up?
The Evap purge valve can cause those symptoms if it's failing.
There are other things that can cause them too but it's the first thing I think of.

 

[fms 19’ Gt]

Does it happen to coincide with a fuel fill-up?
The Evap purge valve can cause those symptoms if it's failing.
There are other things that can cause them too but it's the first thing I think of.

I don’t believe so, I’ll usually go 6-8 days between fill ups and haven’t noticed it directly after doing so… it could potentially be the fuel from this specific gas station though, I don’t really fuel up anywhere else. Thanks for sharing your idea, I’ll pay more attention next time I fill up the tank

 

[Coyotebawl]

Had similar issues with my 19 gt last year, I changed all 4 VCT solenoids and has been good ever since .

 

[Sig556]

Check your O2 sensors for carbon build up. They can be easily cleaned and not needing replacement.

Sponsored