Why does the engine starts revving when put in drive or reverse? on 2003 Dodge Ram Van 2500

Yesterday the engine started to rev-up when put in any gear, like your power braking a little. If you take your foot off the brake, it accelerates to 5 mph on its own rapidly, then lets up. While stopped, if you put it back to neutral or park, the rpm's shoot up for a split second, then drop down to normal. Also I tried pushing on the accelerator while at a full stop and it is revving on its own, and nothing happens. Accelerator only works after truck is on a roll on it's own. It is also blowing a little grey smoke when stopped and revvin. Never smoked before. No smoke once on a roll. Other than this, it runs and shifts normally. It was put on diagnostics and everything was normal. No one I've talked to knows what is causing this. Hope someone can help.

by in Creswell, OR on July 09, 2013
1 answer
ANSWER by on August 24, 2013
Hi,All problems don't show a d.t.c. so I've been learning.High idle speeds can be caused by vacuum leaks or a sticking idle control motor.Visually check the throttle cable first for binding.Run the engine and listen for hissing noise from vacuum hoses or spray soap water on the hoses and if the engine idle changes you know you found the leak.Also check the p.c.v.valve by pulling it out and feel for a vacuum and see if it rattles which means it is good.To learn where all these parts are on your model consult a repair manual available at auto shops.A vacuum leak could show up in the brake pedal too. If the brake booster is affected the pedal will feel hard to press.The vacuum hoses are connected to the intake manifold or throttle body.

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