Hey can anyone help out was driving today after getting my car back from mechanic a week ago car started lagging and hesitating when I gave it gas then check engine came on and started revving up and down and was idling at 2300 rpm I shut it down and towed it home

I have an ap1 with kpro , 4.77 and few other little things nothing major last week my kpro burnt out on me for the second time in a month my mechanic who I don't trust changed my engine wiring harness and took out the speed adjuster not sure what it's called since I don't know too much about cars Any help would be great thank you

 

And also the error code that came up on my kpro was p1519- idle air control valve circuit malfunction. Then when I turned on the car again it disappeared

Thanks

 

Higher RPMs at idle sometimes are triggered by a vacuum leak. Check your vacuum hoses by spaying some WD40 or similar near the hose ends and see if the engine speed changes. Vacuum leaks also will affect your drive-ability. If you don't trust your mechanic, why use him

 

Hunting idle, and high idle are both key symptoms of a vacuum leak. You can also find it with smoke:
https://www.youtube.com/watch?v=zMok2y05jNE

Or WD40/Carb Cleaner:
https://www.youtube.com/watch?v=9CPqbaSgcok