When I strat my mazda b4000 the idle sit at 2000 rpms for about 15 to 20seconds then drops to normal if I give it gas then let go of the pedal it sits at 3000 rpms for about 20 seconds then goes back
Okay, that's sounds pretty normal to me, unless the throttle cable is fraying and causing the accelerator to hang up? But that should be noticeable at other times as well... and dangerous. Is there a question in there somewhere? Modern FI vehicles do this for several reasons, bit the biggest is to help warm up the catalytic converter as fast as possible to bring it to full efficiency.
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