Engine revs at startup

Question

Hi since a bought my car (used) noticed that sometimes when starting the engine it spikes the rpm to much. Is not big deal I know but I'm not sure if is normal because it doesn't always do this, almost always but not always and because it doesn't feel "natural" at all, is like it revs on propose after starting. It starts, revs up to like 1500(normal) keeps it for half a second but then when you would expect the rpm to drop it jumps again to 2k 3k and the it drops to idle.

Only does this when the engine is started already warm, cold starts are fine.

Is a vw mk4 1.6 NA, throttle body is driven by wire

Answer 1

That's easy turn key on to all lights on and push the peddle all the way to the floor and then foot on clutch and turn key and van wont rev on first start it will start as normal

Answer 2

In these cars, this is usually a sign of a dirty Idle Control Valve. It's situated right in front of the throttle body. Take it out, give it a good clean with engine cleaner, spray some WD40 on it for lubrication and put it back. It should take care of your problem.