Missing on 2004 Hyundai Sonata

from full stop or idle - misses on start to accelerate at lower speeds once at cruise seems okay - new plugs / filters / mechanic also had manifold cleaned has 128,000 service - Service record is to perfection

Asked by for the 2004 Hyundai Sonata
Your car has On Board Diagnostics 2 (OBD2). Does this misfire cause the Check Engine Light/Service Engine Soon light to come on? A mis-fire should cause the check engine light to come on even if the light is not illuminated information to help fix the problem may be stored in the on board computer in the car in pending code information or live data stream information. I have seen ignition coil intermittent failure not set a code even though it was obvious the car had an ignition problem under load. Vacuum leaks at the manifold can also cause drivability problems, this should show up on a scan tool if the fuel trim figures are off.
Thanks that helps -
The engine light does not come on -
but it definitely misses during idle very noticeable - and upon slow acelaration from stop to speed - but if If floor it its perfect smooth as silk and then okay at cruise -

I will have mechanic check out per your suggestion - they sure are baffled but I think good crew

Thank You
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