Q: High RPM in drive and slowly picks up to 50 mph

asked by on August 14, 2016

So a few months ago my car began surging in stop and go traffic sometimes almost causing curb checks and fender benders. And my car slowly speeds up to 50 mph. I can put my car into drive and let go of both pedals and it will accelerate and shift by it self, going 20 to 30 in roughly 5 to 10 seconds. I have checked for vacuum leaks, changed the MAF and cleaned them, changed the IAC twice, changed the TPS the throttle cable and cruise control cable feel free with some play, I have also cleaned the throttle body out and used tons of fuel system cleaner. It just had a full tune up 6 months ago, except fuel filter which I am replacing due to some hesitation and hard starting. I have also noticed while coasting down the road if I tap my gas the RPM's actually drop slightly but pick up normally as I depress my accelerator pedal. My car is not equip with an EGR valve. I am very very stumped and I feel like I've tried everything in the book. Car idles fine between 7 to 9 hundred. Help Please!!

Throttle Position Sensor Replacement $129.21 - $646.10 Get a Quote
Fuel Injector Replacement $379.42 - $3631.88 Get a Quote
Car is hard to start Inspection $79.99 - $89.99 Get a Quote
Engine hesitates during acceleration Inspection $79.99 - $89.99 Get a Quote

Hello. From what you describe, it would appear that you have already addressed many of the possible sources of the issue. A few other things I would check are the throttle position sensor and the fuel injectors.

The throttle position sensor is an electronic sensor that detects the position of the throttle plate. This is an important signal to engine calculations and can completely disrupt the engine management system if it gives a bad signal.

Another thing I would look into is the fuel injectors. Bad or leaky fuel injectors can sometimes produce the symptoms you are experiencing. If enough fuel is leaking from the one or more of the injectors, it may cause the vehicle to experience all sorts of issues.

A problem with either of these two components may cause the vehicle to experience hard starting and hesitation, as well as the distinct acceleration problem you are having. After that, I would then begin to look at other electrical components, such as the injector module, or even the main engine computer. If you need further help with this, a certified technician from YourMechanic can come to you to test the vehicle and determine what needs repair.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

What others are asking

Very Loud Strong Vibration when transmission is engaged.

Hi there. What seems to happen is the input shaft on the transmission was not turning and the transmission was lockup internally. This caused your engine to raise high up and make the engine fully extend the engine mounts. When...

Multiple misfire codes and hard shifting

Hello. I would start by doing a compression test. From the codes you are getting to the way that is is running and the sound that you hear it sounds like you have a failed valve seat. When this occurs...

MAP Sensor - 2001 Chevrolet Suburban 1500

Hello and thanks for your question. Check the harness to the MAP (Manifold Absolute Pressure) sensor for voltage. There should be a 5 volt reference that supplies power to the sensor. If you do not have power to the MAP...

Car overheats

It is great to see that you have been trying to tackle your Corvette's overheating concern head on. From the description provided it seems that a lot of components dealing with the cooling system were replaced. From that, I can...

Car not accelerating

From the information provided about your Saturn L300 it appears that oil and coolant are indeed mixing and this is not a good thing. Usually when oil and coolant mix, this is an indication of a leaking or blown head...

I can not locate the starter on my 2007 Chevy Impala. I did go to you tube but the two vídeos were not helpful. 2007 Chevy Impala

Hello - the starter on this engine is located on the driver-side, front (of the engine/vehicle). It is best accessed from below the engine - and unfortunately, there are a lot of hoses and heat shields in that area. For...

Speakers not working

It sounds like the amplifier is not working. Check the fuse for the radio amplifier. If its blown, replace it with the same rated fuse and see if the sound comes back. If not, the amp has most likely failed....

Loss of power in engine

The problem may lie within the fuel injection system from what you're describing. The injectors require a proper amount of fuel pressure and they also stick on some certain year models. Depending on the year you have, it may require...

Car started stalling after being stopped in traffic - 2015 Infiniti Q50

Hello. There are a few things that can cause this, but the most common cause of this is a failing throttle body. I have changed a number of these for similar problems. If the throttle body is fine, then it...

Related articles

A Buyer’s Guide to the 2012 Chevrolet Captiva Sport
The The 2012 Chevrolet Captiva Sport is a brand new vehicle and is an eco-conscious crossover SUV for the environmentally friend consumer. It comes standard with many features, but also has many available options so it can suit any buyer’s...
The Best Used Cars to Buy If You’re Single
When When you’re buying a vehicle that needs to meet the requirements of all kinds of passengers the process can prove to be rather tricky. However, if you happen to be single, you’re the one in control, and your list...
A Buyer’s Guide to the 2012 Chevrolet Suburban
The The 2012 Chevrolet Suburban offers large amounts of space to carry around a growing family or to transport supplies to your favorite camping spot. It is available in heavy duty and half ton models. Key Features The 1500 Suburban...