Idle issues . Please help

[59abe59]

I’ve had my 2016 mustang GT for almost two years now . I only had an exhaust on it until recently .

It started 2 months ago , I was at a stop light in neutral and the RMP started fluctuating but I didn’t think much of it . Later it started happening more and more and it stalled on me a few times. First thing I did was change the spark plugs and coil packs and nothing , then cleaned my intake and MAF sensor and it some what went away but then came back worse . Then I noticed there was a crack in the intake tube where the hose attaches so I got a new intake . I purchased the Power pack 2 that came with intake tube and 87mm throttle body . Took me 3 hours to do the install , car drove like a dream , no issues . And now it just started happening again . I switched from Costco 93 to BP 93 and still have this issue .
Please any help would be appreciated

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[Grimace427]

Step one is read codes. If no codes(unlikely) I would test for vacuum leaks and also see if a single cylinder is misfiring. Never blindly throw parts at a problem.

 

[59abe59]

Step one is read codes. If no codes(unlikely) I would test for vacuum leaks and also see if a single cylinder is misfiring. Never blindly throw parts at a problem.

No codes at all
I had a misfire code before but then I changed the spark plugs and it went away .
How do I test vacuum leak ? Am I supposed to smoke it out ? And using what ? My local mechanic wants 90 dollars for a smoke test and I’ve already dumped enough money on parts

Thank you

 

[jrsimon27]

It could be a crack manifold.
Check it out.

 

[NoVaGT]

It could be a crack manifold.
Check it out.

Yep.

I had a cracked intake manifold. I got misfire codes.

 

[Evil550]

I had the exact same thing going on. You can read it here. Ended up being cam phaser and vct solenoid


https://www.mustang6g.com/forums/threads/2016-mustang-gt-idle-dip-and-stall.114262/#post-2520316

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