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!!

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


Experienced Mechanic?

Earn up to $70/hr

What others are asking

Advice on buying a 4-wheel drive vehicle with minor and major repairs
Minor are the stuff like brakes, water pump leaking, radiator caps with holes in them - stuff that doesn't cost that much to fix and what you can easily do by yourself. But, if the transmission or the engine have...
Alternator squeaking
Hi there. Most of the time if the noise is still there after replacing the alternator it is because the squeak is coming from the belt or another accessory. The belt needs to be replaced and the tensioner checked to...
OBD2 error
You should be able to check the vehicle owners manual for the location of the fuse (https://www.yourmechanic.com/article/how-to-check-fuses-by-rocco-lovetere) that will power the diagnostic port. The fuse is not always the same as the accessory or cigarette lighter socket. If you would...
Anti-theft preventing car from starting
Hello. The first thing I would do is try to reset or disable the anti-theft system. This can be done by locking the doors with the power lock, and closing all the doors and the trunk. Then you wait 30...
Won't drive forward only reverse
Hello...there is a fault in the transmission of course. However, check your transmission fluid level first. If fluid is REALLY low, you could have an issue like this. There is a mechanical linkage in play when you shift into drive....
Shift lever locked - 2006 Volvo S40
Hi there. The shifter in your vehicle has a lock solenoid that locks the shifter (https://www.yourmechanic.com/services/shifter-interlock-solenoid-replacement) in Park until the key is in the ignition and the power is turned on. You will need to remove the shifter from the...
Speed dropping suddenly while driving
If this issue is occurring while you've engaged the cruise control, then this may be caused by a bad or failing cruise control brake switch (https://www.yourmechanic.com/services/cruise-control-brake-release-switch-replacement) or transmission speed sensor (https://www.yourmechanic.com/services/transmission-speed-sensor-replacement). If this issue is happening with the cruise control...
cost to replace the brake control and power module on 2006 prius
Hi there. Unfortunately, this is not a service our mobile mechanics offer; due to the complexity of the service and the need to program (which can only be done at an authorized dealership or Toyota repair facility).
Why do I have no acceleration
Hi There, It sounds like you are describing the symptoms of a failing throttle position sensor. The throttle position sensor (https://www.yourmechanic.com/services/throttle-position-sensor-replacement) monitors the throttle position of the throttle plate inside the throttle body in relation to your foot position on...

Related articles

2012 Toyota Camry vs. 2012 Chevrolet Malibu: Which One Should I Buy?
Mid-size sedans are the perfect family vehicle; offering just enough space for you and a few kids, but not so much that a small family will feel lost in them. This class of vehicles is slightly larger than a compact...
The Best Used Cars to Buy That Can Be Towed Behind an RV
Summer Summer is a great time for a road trip, but often travelers like bringing all the conveniences of home along, in the form of an RV. Then they tow their car behind it – sometimes this practice is called...
How to Replace an Injector Control Pressure Sensor
Diesel engines have an injector control pressure sensor that fails when there is hard starting, decreased power, or an illuminated Check Engine Light.