Q: RPMs drop and car shakes?

asked by on March 13, 2018

I have a 4.7L V8, when im accelerating if I hold the gas pedal down in one spot (to maintain a certain speed) my RPMs will eventually drop to around 1300 after the truck shifts and my truck will start to vibrate? If I remove the gas pedal and press it again the RPMs will kick back up to 2k then shift and accelerate like normal.

My car has 139200 miles.
My car has an automatic transmission.

Hi again Jarod. What you’re describing is often a sign of a vacuum leak, exhaust leak, fuel restriction or faulty mass air flow sensor (designed to help mix air and fuel together). To be honest, there are more than a dozen possible mechanical components that can cause this issue, even a worn out torque converter. It’s also possible that the coolant leaking from your engine (as indicated in your last question) is causing an electrical problem with ignition timing components or even fuel-related sensors. There are simply too many possible sources to give you some solid repair advice in this case. An onsite inspection from a professional mechanic is best.

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