I need to know the answer of my problem on my 2005 Hyundai Starex GRX Disel. My tachometer instrument panel is shaking up and down between 1 and 2 while the engine is one and not moving. when the tachometer moves up and down, it make the engine accelerate as if it I am pressing the acceleration pad. At frist I thought that the problem is my disel injection pump which was tested and replaced without solution. i also had done an auto scan for electronic problem, it shows up something called FUEL INJECTION ADJ, but we delete the problem and turned on the engine to see if it comes again on the auto scanner, but it did not appear.
What is the car problem???